Think a bit further ahead.

The local club I stopped going to years ago had singarounds three or four weeks each month. That makes about 40 a year. Singers would typically get 2 slots a night. So if your repertoire is 12-15 songs, you are expecting your audience to stay interested in hearing the same song 6 times a year.

Memorization-dependent amateurs can't do it. The only way you can not be boring in that situation is to use a written copy. And have the skill to use it effectively - a skill which has declined sharply in my lifetime (though it persists in genres outside folk).

GUEST above with the point about hymns was me, cookie got lost.