I'm so grateful to my younger self for choosing to learn Japanese, since it familiarized me with this software. I use it for everything and it's an incredible way to learn something new every single day without having to put much effort in or find the motivation to do it. Soon I'll have all the african capitals and the entire periodic table memorized and I've also got decks related to nordic runes, korean hangul, morse code, famous artworks, recognizable buildings and recently classical music and coding in bash.
All of this is probably inferior to reading a book, but I suck at reading and this is leagues better than doing nothing.
My favorite is the Japanese history deck I found, which has thousands of cards and is fully in japanese, so that I'm technically also immersing.