I think you are getting a bit confused with volatile crypto currencies like BTC and an NFT.
Lets say I buy a ticket for a gig from ticketmaster. I get an eticket which is just a QR code. It would not be too difficult for ticketmaster to set up an NFT system on their backend. Your eticket is now an NFT, nothing has changed from the user point of view and the artist still gets their cash money for ticket sales. Or even better an independent platform could be set up that takes less fees than ticketmaster and gives more money to the artist.
The only difference is now your eticket has a receipt on the blockchain that in the future may or may not have value, ordinarily your eticket would have no value after the gig...
I am not some advocate of NFTs by the way, I couldn't care less how you get your music ticket, but I do think this is how it is trending, certainly for larger artists who can draw massive crowds. For the smaller gigs like you said, I agree cash is king and NFTs would be pretty useless.