Scooters could be using NFC/RFID payments today (e.g., Apple pay) instead of QR codes. So you could just walk up, tap your phone, and go. UWB offers no real usability advantage here. Scooter companies don't use these methods because they want you to install their app for user retention reasons.

So what's missing in your scooter use case is a loyalty mechanism rather than a lack of payment technology.