People spend tens of thousands of dollars gambling on what are essentially just PNGs of cute anime girls in gatcha games [0]. Someone else in the thread linked Fate Grand Order which has over $4 billion in revenue. I didn't really understand it until I watched this very NSFW video [1]. The presenter does a great job of explaining what gatcha games are and the history behind them. He also spends $1000 to show what you actually get for your money in these games.

[0] https://en.wikipedia.org/wiki/Gacha_game [1] https://www.youtube.com/watch?v=LvdtJsZpuQ4