I think this might have been a popular solution once, but my guess is that it came with its own set of problems. Hotels often being pretty big (bigger than most churches, which also tend to be relatively open structures), usage of the license free bands from other devices, audible interference (which you don't care about in ham radio or portables as long as you can still understand what's being said, but for music in a hotel even low interference is bad as soon as it's audible)... though admittedly, I have no experience with radio transmitters for that particular use case.
