I agree. I find it really useful for drilling vocabulary, but I struggle it suitable for learning grammar. Conjugation (and declension), sure, it helps a lot, but that’s basically just memorizing facts.

Basically, yeah, it’s great at memorizing bits of information. This makes it great for beginner language learners, as well as those who need to memorize lots of facts (medical students). Otherwise, once you have enough to have a go at your target language, you’re indeed better off doing that instead.

However I still think it’s fine to keep it on the side if you need to keep your vocab fresh–especially for those you rarely encounter in your target language. (Though if that’s the case, do you really need to keep that word in your memory?)