But they require dark room. Where I live in summer it gets dark at 23:00 so you need great curtains or you can’t see anything most of the day. If you have curtains you have to watch everything in complete darkness. This is fine for a movie night but people like to watch news or watch a game with their friends over some food. You also need extra device to handle apps like Jellyfin. Things like BT can be more complicated to set up (my TV handles multiple BT devices nicely).
Projectors are basically great for one or two things (home theater and gaming) but are bad for everything else.