These are always done for photographs. It's not something people should ever use when the projector is on.
I am a HUGE fan of task lighting in the room. That is, one spotlight over each seat in the theater which is on a dimmer. So, you can have all the room lights off, but then turn on lighting over the seats which minimally impact the screen or room but give enough light for reading, eating, and just moving about if needed.
Things like wall sconces, ceiling tray lighting, rope lighting, and other in-room general lighting should be fully off.
There is an argument for bias lighting (behind the screen onto the wall) being beneficial, but I would say that in a proper home theater when viewing movies, this is absolutely unacceptable.
Now, I'm talking best case. In more casual viewing, bias lighting may be okay for sports, etc. and personal preference is always the trump card. Do what you like, not what I like.
But, for a family room setup, I did this set of photos years ago to show how lighting impacts on-screen image quality.