Janie, I can relate to your point about group singing often being uncomfortable for those of use who tend to sing in different keys than most of the group.

But I think some songs are "made" by harmony, especially multi-part harmony, and try as I might, I just cannot pull off harmony as a soloist (without hi-tech help). I'm funny that way.

While I concur in not liking it when everyone is expected to sing along on evrerything, I do think that group singing provides some wonderful music experiences that listening to a series of soloists can't.   While the point has tended to be passed over in this discussion, I think that a primary valid reason for using books or sheet music is to facilitate people singing together "from the same page of the music" and with harmonies added.