fwiw I studied Japanese, but I believe most of this still applies.
It's divide and conquer. When you are reading the book, you are indeed just learning the characters. It's a significant ~2-3 month investment that maybe doesn't make sense unless you plan on living and working in the country. But once you've gotten through it, it absolutely feeds back into vocab acquisition, since the characters are now completely unambiguous to you. Much like how Latin/Greek helps with English, you can also work out what entirely new words might mean if you are familiar with their characters.
I did RTK. I also learned to read around 3k kanji. Turns out it wasn't at all necessary to learn to write that additional 1k Kanji in order to become able to read / distinguish it.
The time is better invested in simply studying how to distinguish visually similar characters. That alone solves the problem directly.
I also did all three volumes and found the extra 1,000 to be a waste. Really polluted my Anki.
> The time is better invested in simply studying how to distinguish visually similar characters.
But you still have to know what you're distinguishing between, which might only arise after repeated mistakes. Heading off this frustration directly by studying characters may not have been the best use of my time in absolute terms, but it did wonders for my overall motivation and made me feel like I was doing more than treading water. Pre-Heisig I was reading specific books intended for foreign learners, while afterwards I was just reading the newspaper.
It's somewhat a shame there isn't heavily curated Anki decks for doing what I call "disambiguation study" where you focus on cards that help you distinguish similar things from one another. It'd really speed things up.
>But you still have to know what you're distinguishing between, which might only arise after repeated mistakes.
I'm learning Korean at the moment and it's particular brutal for this IMHO. Some words have taken a long time to properly understand due to repeatedly mistaking them for very similar words, and there are a lot of these in Korean.
It's divide and conquer. When you are reading the book, you are indeed just learning the characters. It's a significant ~2-3 month investment that maybe doesn't make sense unless you plan on living and working in the country. But once you've gotten through it, it absolutely feeds back into vocab acquisition, since the characters are now completely unambiguous to you. Much like how Latin/Greek helps with English, you can also work out what entirely new words might mean if you are familiar with their characters.