>>585402BASICALLY
Miku if Miku was also Vinny Vinesauce but was also gay buddies with Jerma (who was also Kagamine Rin) but they were all idol singers so actually not like Miku at all.
Streamers wearing animefaces to make them more relatable and (allegedly) discourage doxxniggering, but most of the Holos were minor internet celebrities beforehand so it rarely works.
The culture here is a mishmash of youtuber stans, idol otaku and /jp/ hikkineet, that should tell you plenty if you've gone outside your rock sometime last year,
As for how to get into it... just watch, really. Clipfags exist to help you get past the language barrier but some of the jp vtubers are very gaijin-friendly and the holoENs exist so you CAN catch whole streams in a language you can understand.