Japanese pop culture is something I've spent a vast amount of time on, but don't feel like I understand much at all. Case in point: I just now connected my little monster toys to #Gacha #Gasha #Gachapon #Gashapon.
There are any number of little blog explainers about Gachapon, with surprisingly different tones and levels of scholarliness and irony levels. Here's one:
https://zenpop.jp/blog/post/5346/the-ultimate-guide-to-gachapon