I have got a use for mine in a session, though - it's got a tuner app on it.

One of the reasons the old singers didn't have to have the words is that the older ballads tend to be on the long side. You either know it or you don't. But even so, there was always dispute, for example in the Sheffield Carols variations or the Suffolk tradition. There, it was likely to turn to violence - one concertina player was renowned for his ability to play it behind his head, to avoid damage in the brawl in front. Another managed to sing his piece while attempting to remove the bowler hat jammed down over his ears. And in those circumstances, what good will sheet music do you?

On the other hand, I've just done a few sessions with one of the pro bands: they score the lot. What's the difference between an amateur and a pro? Am amateur practices until he gets it right. A pro until he can't get it wrong. The difference is the pro has the dots to refer to to check what's right, the other sort of remembers how it goes. And yes, the seven pieces in the half-hour set came to close on a hundred pages of music, nobody can reasonably be expected to remember that lot. But then again, you couldn't possibly get a hundred pages of music on a smartphone, nor even usably on a tablet.