I purchased them in 2019 as I was refreshing my general ML knowledge as I was getting deeper outside my particular ML specialty at work. Loaded them into Anki. Wasn't really a fan, but definitely one of those "$12 isn't worth complaining about it and getting a refund from someone who seems earnest" type of situations.

Notably they're not traditional flashcards where I can be given one side, answer the question or repeat the concept, and then check the other side for the answer. Everything is on one side.

Second, lots of different subjects which may generally be good for overall knowledge, but lots of random things I found more specific to data science than ML, which I didn't expect because they're called Machine Learning Flashcards. I do realize data science is kind of a proto ML though.

Third, I found them hard to read with all the colors, some of which didn't scan as well as I would have liked.

To be completely fair, I'm probably not the target audience, but I felt like I was marketed to as if I were.