Reminds me of how wireless keyboards and mice often don't use BT despite it being totally designed for that use case. They use some random 2.4GHz USB dongle. And well there are BT kbms, but they're unreliable.
[0] https://www.logitech.com/en-us/products/keyboards/mx-keys-mi...
There are also some BT limitations at play. Key rollover is capped, and mouse polling rate is lower. But that'd only matter to me if I were playing PC games. Ability to switch devices is a plus for BT.