My mom says it’s helpful for her as a music teacher. It was annoying when she tried to teach me piano and she’d be cooking in the kitchen and I’d be playing in the other room and she’d call out when I made a mistake. But that’s probably just because I was an ornery student. Objectively my mom is a fantastic teacher. Her students all do really well in competitions and my nieces love playing with her. I’m sure perfect pitch is only a small part of it but it helps.