"I don't see sitting round in a group of friends taking turns to sing as a performance, but taking part for the pleasure of doing so."

But whose pleasure? If it's only for the singer's own pleasure it's just self-indulgence. It should also be for the pleasure of the listeners. That requires proper preparation to think about the song, work out the best phrasing, and deliver it to the best of one's ability. That's all I mean by 'performance'. Shouldn't a group of friends be entitled to expect that from each other? And is it really too much to ask from people who apparently love the music and enjoy singing?