This was a good read, thank you! Sorry I didn’t get to it sooner.
Bluetooth terminology is very confusing, especially when you get to Bluetooth Low Energy. In my opinion they shouldn’t have called it Bluetooth Low Energy, they should have used another name entirely because it’s a very different radio protocol than Bluetooth “Classic”.
Anyway, the Mooshimeter does not use pin codes or pairing, just a basic GATT profile over BLE.