Fun Fact: As Saiyans go, Raditz isn't just weak; He's a talentless hack. Nappa is much more talented at martial arts, but his skills are undermined by him being a complete fucking moron.
Raditz is our introduction to the particularities of the Planet Trade Organization - or, well, the Saiyans since the PTO didn't quite exist as a concept yet when he showed up.
Toriyama only came up with the PTO later in the arc. It's honestly kind of funny; Vegeta's referred to as the "Strongest in the Universe" a couple times in this arc because the idea for Frieza doesn't exist yet. The original plan was that the Saiyan race are the ones doing planet gentrification on their own initiative, but they were almost all wiped out by a meteor so if we take out Strongest in the Universe Vegeta, we'll put an end to it.
So all this stuff like the spaceship pods and Scouters that was original Saiyan equipment and methodology got retooled into being PTO equipment and methodology.
But I digress. We meet Raditz and he's unlike anyone we've seen before. He immediately starts shit with Piccolo because they're both assholes, and we see how he operates.
He has a little doodad that reads off someone's "Battle Power" into a flat, easily digestible number that even a child could understand. This is the industrialization of martial arts, simplifying it into something that can be replicated and mass-produced.
It's the difference between teaching swordsmanship lessons in your dojo versus handing someone an AK-47 and telling them to go shoot the enemy.
This is the key distinction between the Saiyans and Earthlings, that made Goku - A Saiyan raised on Earth engulfed by their martial arts philosophy - so formidable. The Saiyans and by extension Planet Trade's culture is built on capitalist efficiency. Their warriors are carefully measured, analyzed, and matched with suitable challenges. They aren't trained. In fact, Vegeta scoffs at the idea of it.
They measure their fighters and quantify their abilities into a number, then select the right target that matches that number. Those warriors become stronger through fire and frenzy, rather than by studying principles of martial technique.
Consequently, upwards mobility doesn't seem to be a thing. Nobody in the PTO got to where they are by working hard and improving themselves. Every single one of them is naturally gifted, coasting by on whatever privileges their birth afforded them. Especially Frieza.
They aren't practitioners of an art. They're cogs in a machine.
Raditz believes these distinctions made Goku weaker.
He has no idea. The limitations of the PTO's methodology is a recurring theme in the Saiyan and Namek arcs.
Raditz is a low-class Saiyan. By virtue of being a Saiyan, he's still unbelievably powerful compared to the terrestrial races of the worlds he's sent to. But power is all he brings to the table; He's an unrefined juggernaut who coasts by entirely on Big Number Go Brrrrr. Philosophically, Goku is unimpressed.
Coming from Goku, that's a pretty sick burn. He's already lost to Raditz once; He knows how Big Number this guy is. But he can't bite his tongue at Raditz's oversimplification of his art.
As a fighter, Raditz delivers what he promised. All he has going for him is Big Number Go Brr... but it's a really big number.
Raditz is impossibly strong, impossibly fast, and his basic-ass ki blasts are impossibly powerful. The gulf between Goku and an adversary has never been so huge before.
And yet, for all his power, he is repeatedly startled and befuddled by Goku and Piccolo's training and technique. These weaklings are breaking out abilities he didn't even know were possible.
Raditz watching Goku power up the most basic ki concentration technique on Earth and exclaiming "WHAT IS THIS SORCERY!?" really tells you everything about the PTO's methodology, doesn't it?
Raditz falls for every trick and every shenanigan that these guys have spent their careers honing, forced to rely solely on tanking attacks with his tremendous Numbers.
This dipshit hasn't even trained the weakness out of his tail.
Goku was fifteen years old when he trained his tail and eliminated this vulnerability.
Raditz is less proficient than Goku was as a child. This isn't even the PTO's flaws manifesting through Raditz, either. Nappa and Vegeta trained their tails.
"LOL What kind of a useless clown doesn't train his tail?" ~Nappa, probably. Oh, wait. No. Actually.
Raditz is limited by the philosophy of the Planet Trade and he's also on the weaker side of Saiyans, but he also sucks even without taking power levels into account. He brings absolutely nothing to the table. He reads someone's number to tell him in advance if they'll fall down when he punches them, and then he punches them if the number tells him he's clear.
Raditz isn't a fighter. He's a bully with a gun.
For his part, Nappa is a more advanced version of Raditz. His Big Number Go Brr is even bigger than Raditz's and he's familiar with more advanced techniques beyond "Throw this ball of ki at your face".
As a front-line fighter, Nappa is unbelievably tough. Blow after blow and attack after attack, he never gives as much as it feels like he should. No matter what they do to him, he keeps getting back up and coming back, more bloodied and bruised than ever but ready for another round. He is unbelievably resilient.
Fighting Nappa feels like an exercise in futility. You're going to have to kill this man to put him down because he'll accept nothing less. Even when Goku takes the field, he finds himself at a loss with Nappa's absolute unwillingness to take the hint and lose consciousness already.
Nappa is a brick wall. Goku only finally manages to end this by breaking his spine so he can't keep getting up again.
That is what Nappa brings to his table. Though it's worth noting that his Sisyphean endurance is something Vegeta shares as well. It's not unique to Nappa. Fights with Vegeta are every bit as much of an ordeal as this bout with Nappa was.
Saiyans are hard to put down.
Nappa's biggest weakness, however, is simple: Like Raditz, he's coasting on his brute strength. He doesn't pay attention to what's happening around him, and is easily blindsided by sudden attacks from other fighters in this brawl.
Or baited into incredibly poor decision-making.
For all his Saiyan might, the Earthlings would have killed Nappa well in advance of Goku's arrival, if he didn't have Vegeta to watch his back. I'm half-convinced the only reason he trained his tail is because Vegeta told him to.
Nappa is very much a follower. He does what he's told. He's honestly a better Saiyan than Vegeta in the sense that he. Like. Cares about other Saiyans? His kneejerk reaction when Vegeta suggests taking Earth's Dragon Balls is that he wants his friend back.
And he's filled with eugenic fervor for the glory of the Saiyan race when he finds out what mixing Saiyan and Earthling physiology can do.
Fun little side note: "Super Saiyan" was originally the term used to describe Gohan's hybrid abilities before it was recontextualized to mean something else on Namek.
It's honestly interesting to look at their interactions and realize that Vegeta is a cruel, monstrous, selfish bastard even by Saiyan standards. Vegeta is uniquely wicked within this culture of for-profit colonizing murderers.
But Nappa defers to Vegeta every time. Vegeta tells him, "No, you're wrong," and Nappa pivots to supporting whatever Vegeta just said instead. Nappa obeys.
But he doesn't listen. Vegeta and Nappa were following the action while Raditz was fighting Goku and Piccolo. They saw all of the strange anomalies that occurred, that Raditz couldn't comprehend. Vegeta spends this time thinking about what this means for Earth and re-evaluating his assessment of the foes to come.
And he adjusts accordingly. From the moment they arrive at the fight, Vegeta pegs overreliance on the Scouter's readout for the vulnerability that it is.
Like. He says this. He acknowledges that he understands. And not five minutes later:
Even then, Nappa flat-out ignores The Numbers if he doesn't like what's printed on them.
Nappa and Vegeta both disregard the printout this time, but in different ways. Vegeta observes that Earthlings suppress their ki, presenting a smaller number than their true ability. So when the Scouter says 5000, that means Goku's true level is likely well beyond that.
Nappa observes that Goku is probably weak so that's stupid and you're wrong.
Nappa just does things. He doesn't think or pay attention to what they're doing. He destroys a city as soon as they arrive, and Vegeta immediately lays into him for what a fucking idiotic thing to do that was.
He's a beast on a chain, barely restrained by his deference to Vegeta. Powerful, seemingly unstoppable, but needing Vegeta to hold his hand and walk him through the higher concepts of combat and martial arts.
An absolute fool. But a Saiyan elite fool.
