Comment by SamPatt
A few uses for me:
• Memorizing Geoguessr metas. Made it to Master I rank this way.
• Memorizing new words. When I come across a word I don't know, I make a new flashcard for it.
• Memorizing things about people. My wife's favorite ice cream flavors, which spices each of my children dislikes, etc.
Anything I want to memorize but wouldn't be exposed to frequently enough in my day to day life. Flashcard review takes only a few minutes each day.