There's a lot of advice for learning Japanese out there, and sometimes it just pisses me off.
Now, it's always good to look at why something irritates you in case there's a grain of truth that you're not seeing... or wanting to see. I mean, some things are unavoidable - like there being quite some work needed to learn Japanese. Especially if you want to see some results. But...
Maybe an example will help. IIRC, the YouTuber was called Mochi. I just browsed through her tips what is needed to learn Japanese, but if you want me to distill it for you, it was essentially a brute force approach, not very different from how Japanese students learn it. Using her app for Space Repetition (SRS) was basically the only nod to anything that has happened in the "learning Japanese for Westerners" space at all. I bowed out at "learn to write kanji" as a needed step.
Now, undoubtedly, writing kanji a few times can give some insight into kanji themselves, to learn concepts like stroke order. It isn't especially hard, either. And if you have problems telling certain kanji apart, this might help fix them into your brain. But in general, from my own experience, I disagree.
You see, I started out by learning to write 1,000 kanji. But now I have largely forgotten all the connections between meaning and kanji built through this exercise already. Maybe the effort to learn kanji that I've seen before through this method is lessened, but I still learn them all over with Wanikani.
I'm not claiming she said that only learning to write kanji was enough. That would be misrepresenting what she said. But if I were to paraphrase it another way, she basically said "Learn it how I did. Trust me, I'm Japanese."
I've been talking about SRS a lot, and so you might think I'm a big proponent for Spaced Repetition. To that I would say... it depends.
You see, SRS by itself is only a slightly better way to do rote learning so that you are more likely to retain it in the long-term. So if somebody tries to sell you their approach by saying they use SRS (and nothing else), all they offer you is to schedule your rote learning for you. ("Anki", as I recently learned, the name of the most popular free SRS software, may simply to mean "memorize" - because that's the Japanese kanji/word for it.)
If you want to rote learn Japanese, be my guest.
I mean, it's a valid approach. It's not the fastest or most intuitive, but it's a big part of how Japanese learn the most vexing parts of, well, Japanese, aka "reading and writing Japanese."
But the general majority of Japanese dispensing advice on learning their language on the internet seem frankly uninspired. If you're looking for strategies matched to your own way of retaining information, it's quite hit and miss. (Wanikani has a Japanese founder, though.)
I have written kanji, I have trained them over two different types of SRS. But at times they don't come to mind directly, and then I'm glad if I can recall the mnemonic story I've associated with them. Because I might not recall the meaning of the kanji directly, or its readings, but maybe any of the other ways I stored them will come to mind. But that's not the effect of SRS (or SRS alone), but of an alternate learning strategy, not simply relying rote memorization.
What is your goal? What are your priorities?
But Mochi is not the only one. NihongoDekita is someone I like to watch YouTube shorts of. She wins the prize for making the lamest argument why you should learn to read Japanese (= kanji + hiragana + katakana) natively. She puts an English sentence in Japanese letters and reads out loud and says "that's not English, that's Japanese" as her argument why Romaji is not good enough for learning Japanese.
But... while Japanese is incapable to produce the sounds English requires, you can read Romaji and produce exactly the sounds Japanese requires. (You would make yourself aware of how to pronounce it properly, but the same is true for learning Hiragana as a Westerner - or any language in the world transcribed to Roman characters.) Talk about a badly made argument.
Your learning of Japanese would certainly be incomplete if you didn't learn how to read it. But then your learning of Japanese is also incomplete if you don't learn how to write it. Or if you don't learn Kansai dialect. Or if you don't learn conversational variations how contemporary Japanese change Japanese from "proper" to day-to-day speech. Etc.
But there's one question to cut through all of this: What do you want to achieve?
Do you want to learn to read manga originals? Learning to read is not optional for that. Do you want to learn basics of face-to-face conversation? Romaji is a viable way, then. Same for understanding what characters in anime say (if you are willing to ignore all the displayed kanji). None of these require being able to print kanji. And so it goes.
Learning kanji would be a bad investment of time if your primary goal or priority is to learn to converse fast. It will majorly slow you down. Ironically, it will slow you even more down if you learn less! Learning 100-200 of the most common kanji is harder because some of them are more complex ones and since you wouldn't know the radicals they are composed from from other kanji, you have less to anchor them in your brain with.
Wanikani has been criticized for not preparing you for the JLPT N5 and N4 tests, but its goal is teaching kanji in a good way for building a bottom-up understanding, not get you to the goal of the most common the fastest. You go from building blocks to bigger structures, and you build from what you know. Which helps retention in a different way. Simply using SRS would not have the same effect for retaining the kanji because they would look still alien to you. Frankly, they would, even if you learn to print them without a structured approach.
The reality is, your learning time is likely limited. So might be your patience before you see results that reward you for your progress.
Yes, if you learn kanji, learning to print them can anchor them in your brain better. But if you want to learn to print them from scratch, there's an additional investment of time. In the Heisig method, you would arrange your mnemonic story so that you can actually give yourself hints what to print in what order. That's a more complex requirement for a mnemonic story than merely coming up with a story that helps you spotting the elements in any order to remember what kanji this is. Kanji elements can become quite crowded, and can appear left/right, above, under, etc. Then you need to retain some memory as to how to arrange the elements in the given space so that you can actually write the character properly.
The same time might be used to learn more kanji and vocab, or to practice grammar, tackle some graded readers... And it requires you have time to sit down and do it at a desk or table, pretty much. Commute times, in comparison, might be usable only for an app or index/flash cards, or reading.
Each learning strategy needs to evaluated for how much time it uses, how effective it is, and what kind of structure it builds for the future.
So, for example. If your goal is to take the JLPT N5 test ASAP because you need it professionally, Wanikani is not your best choice. Yes, by now I've covered practically all of them. I referenced two separate lists, and they basically say I have 99% of them. But they did not come in that order. And when I go over Bunpro's N5 vocab deck, there are lots of kanji in there that are in neither list.
I, myself, find that okay, since my goal is a complete learning of the Japanese language, not a test, but if you really have to, you might rightfully get frustrated by such "you will eventually get there" approaches. (Heisig is way worse, after all.)
There's no one true way to learn Japanese.
There are always compromises you make. And if you're taking classes, the compromises your teachers make. Reevaluate them over time and compare them to your goals. You can approximate what works best for you as you learn about the learning of Japanese itself.
Over time, unless you do courses in a fixed system, you will have to structure your Japanese learning yourself. And even then, if you apply your Japanese in some way in the real world, you need to come up with strategies to come up with the missing parts that class didn't cover yet. So being aware of your goals and priorities and comparing your current approach with them once in a while can give you a valuable sense of direction.
