"In Chinese, words are really compound words. For example, 熊猫 means panda. But 熊 means bear and 猫 means cat. This makes these unbounded morphemes, which is different than what we do in the Indo-European languages. And Chinese is composed of radicals that make things harder."
I'm intermediate in Japanese (conversational + able to read at an N2 level, albeit slowly), and my first response to anyone who says they "learned X kanji" is "how many words do you know?"
There's probably some value to learning the meaning of individual kanji in isolation, but it's very limited (especially in Japanese). Most words have only tenuous relation to the meanings of their individual kanji, and "learning kanji" is kind of a crutch for beginners to pretend that they're making rapid progress.
I suppose from that perspective, "learning X kanji in Y days" is a useful meme, because it pushes people to quickly move on from the approach. But that said, for most learners, it's much better to simply start learning words.