Stewart, I prefer big-print song sheets for use IN group singing. They can be placed on a stand and glanced at PRN, without people's faces being buried in them. (And I'm not saying they need to be used on all songs, just from time to time.)

There's (unfortunately) a reason why RUS is often referred to as "Rise Up Squinting."

In my professional gigs I sometimes have a giant-print song sheet in front of me on a few selected songs (especially songs in other languages).    They're not obtrusive, and they do come in handy when your mind goes blank in the middle of a song and you can't remember the first word of the next song.   One glance is all it takes.

But I do agree people need to learn to use both their memory skills and info from auditory and visual sources BESIDES books and sheet music.