@latein @s I think it only worked for me because I did this since I was a child, so I spent a lot of time on it while my brain was still young and fresh. I don't think this approach could replace actually studying though. You do learn the English words, but you are going to use them by recognizing patterns instead of properly learning grammar, which means that what you are actually doing is memorizing and repeating instead of being able to communicate properly with your own words.

>it didn't seem to be so for Japanese when I was a weeb

I think you can learn Japanese words in spoken form with anime, which is useful to notice if the subs or localization is wrong or missing things, but if that's all you are doing to learn Japanese it's going to be just for this limited use.