A reminder cum prompt is one thing (blue tac'd notes on guitar with key, first line etc) have been part of my style for almost forty years.

I also sympathise with those who perhaps cannot physically retain words.

But increasingly, it has led to less need to practice with the resultant drop in quality. If you have to learn a song, you end up crafting and honing it. A singaround I sometimes go to has at least three people I know who sight read three chord wonders for the first time, badly, rather than learning and therefore trying to entertain with songs. The saddest part is, all three of them are capable of us enjoying their songs rather than timing the emptying of my glass accordingly.