Yeah, to me personally it just seems like treating the other person (e.g. a cashier or waiter) like a tool or utility rather than a human being. Even if your music is paused (which they can't know)

Have you asked an actual cashier what they think? They handle hundreds of people every day, do you really think they consider it rude if people don't chat them up? You can smile and say hello and thank you with or without headphones. This once again seems like a cultural divide, as a German I'm happy if noone talks to me outside of smiles and hello/goodbye, this might be different in the anglosphere.