There seems to be a lot of research about SRS but I never see any research about what makes an effective SRS flash card. Maybe it’s different for every person and/or subject. My foreign language skills improved considerably once I stopped putting english on my cards at all and used only the target language + pictures. But, like the person you replied to, using Anki for anything other than language learning has been mostly a waste for me. I do suspect it’s more to do with the decks I’ve created than with the SRS process.