That’s kind of my point. No one at subway is calling themselves artists, it’s insulting and they don’t like it. You answered your own question, the answer is: they don’t.
In instances where they use their given title it’s probably for convenience. I’m an EMT, when I was doing interfacility runs for a private ambulance company (aka not doing the expected work of an EMT) I didn’t call myself an ambulance driver or professional insurance fraud fall guy, I called myself an EMT because it was easier to use in day to day conversation. If someone wanted to talk about it I would explain the nuances but I’m not gonna do that every time someone asks me what I do for work in polite conversation