Same for Anki, Notion, Zettelkatsen etc. Even ignoring the setup cost, it costs as much effort to insert in something as it does to retrieve it. The value prop tends to be low for individuals.
A technique I've found that works for learning languagea in Anki is to generate or download massive deck, suspend all of it and then whenever I encounter an unfamiliar word in the wild I unsuspend it and set it up for review. Takes like 5 seconds.
As much as I love Anki there is enormous friction in creating the cards, especially as a beginner. And you very easily get overfitting when you keep seeing the same question.
