One of the most meaningful reasons to use Luke Skywalker–other than it makes sense story-wise, given Luke’s motivations at this point in the timeline–furthers all of this. He and Grogu are similar, they are both fuck off powerful in the Force. This is why the mentions of Anakin in “The Jedi” are so important as well, because Anakin was also just fuck off powerful in the Force and he fell prey to his feelings and attachments (the desire to own people, beyond just loving them, he was afraid to live without them and would do anything to stop it).
Luke, having struggled to overcome all that anger and fear in The Empire Strikes Back, Luke struggling to overcome his anger and hurt in the current Star Wars ongoing comic, Luke struggling not to be consumed by his hate and his rage that has him furiously hacking away at Vader when Leia and his friends are threatened.
Luke Skywalker knows what it’s like to have the kind of power that would terrify people and Luke Skywalker knows what it’s like to struggle with anger and hate and fear. Luke Skywalker also knows what internal strength being a Jedi gives him and why that discipline and mental clarity are so important.
Using Luke Skywalker, someone we have seen struggle with all of this and turn to the Jedi ways time and again, someone who has a similar power level of Grogu, someone who has a similar power level to Anakin Skywalker, shows why Grogu must learn to control himself, because look what a fuck off powerful Force-sensitive can do to the galaxy. Luke Skywalker (and his father before him) demonstrate that so incredibly clearly through just how easily he defeats those dark troopers. We saw Grogu already has some abilities, he may get sleepy very quickly, but look what he did to that mudhorn, look what he did to Cara Dune, look what he did to the Stormtroopers. Already Grogu can lay waste to grown men and women and hugely powerful animals in his fear and fury.
And no one in the galaxy is better equipped to handle than that Luke Skywalker, if Grogu actually wants to control himself, no one can help him more right now. That doesn’t mean Grogu won’t come back to Din someday, but right now, of course Grogu wants to learn to control this tremendous power, if for no other reason than look what keeps happening to him because he was born with this ability.