In PPM markets, broadcasters don’t need to rely on people remembering what stations they listened to during the week, instead they have the PPM recording what they listen to… so recall and branding is not QUITE as important (but you still want to make sure people know what station they’re listening to so they tune back in again.)
But for purely ratings reasons… it’s not as important in PPM markets to have a catchy name for people to remember.
I would still think marketing and word of mouth would be one of the main ways to promote your station. A billboard with “Radio 104.5” on it really doesn’t sell anything. Or telling your friend about the new radio station you found would be a lot easier remembering and saying “Q102” than “Radio 102.1”