They all have one of two purposes for being there:

1. I like singing them

2. (a) Someone else wants me to sing them! Which often leads me back to point 1
. (b) I am getting paid to perform a certain repertoire, appropriate to the venue.

If you don't see the point in singing stuff you used to sing, it's probably cause you don't like singing them any more (or think you don't).

After a break from performing, you get to reinvent yourself. One of the big perks of playing music.

W-O
"We don't have much fun, but we make a lot of money"-John Foreman