Hmmm… I’m going to go out on a limb here and say it’s a musician thing.
One of the guitar players for my band wears it but I think he does it to draw more attention to his hand/playing or something. I dunno, I never asked him. I can think of maybe 10 other guys who I’ve seen in the last month with it on, but none of them were in the audience - they were up on stage.
I’m a drummer and my hands are usually flying around quite quickly so it’d be pretty hard to see any nail polish. Plus, it would taste awful when I gnaw on my nails.