I agree with UD
Its like calling girls "chicks", just a little out of place in modern day terminology.
However, "work" is a little too general. YOu could say you "work" as a musician but what does that mean. If you practice that is work too but we still say practice for practice (or do we?)
I do not work as a professional musician anymore but when I did it sure felt like work to me.
It is fun sometimes but it is not fun when you are on the road and your sound system breaks down during the first set the bar owner is trying to run you out of town.

But what would be a suitable replacment for Gig?

What do union musicians call it when they perform live? Practice?

Guitarman