Nope, doing reviews where topics are totally randomized (Called stochastic review) has been easier for me in the long run because I don’t have to categorize things, I just shovel them into SuperMemo and review them when their time comes. One skill you acquire while doing this is you learn how to quickly establish context for an idea since you can’t rely on contextual groupings when you’re doing your reviews. This has helped me learn to summarize information quicker because long term you will be asking yourself “If I don’t see this flashcard for three years, does this question establish enough contextual information that I can answer it?” Most flashcards are only one or two sentences long, since reading a paragraph to review a single card is really monotonous. As far as what info do I remember with it, it started out purely for language stuff, then I started using it for job info, then started using it for more “high class” information like history or science, but also experimented with idioms in foreign languages and then jokes in my mother tongue (English), which has been a lot of fun. I’m pretty convinced that if someone really committed to it, you could learn to be a really good comedian or freestyle rapper by using spaced repetition.