I realize that. But that's just for that machine, but I'm speaking for arbitrary devices.
The protocol hasn't gotten faster in the last few years that I know of.
I've used several with different devices, but most of my direct comparison experience is with an Xbox series X controller paired to the Deck via BT and by dongle, and it's very noticeably more laggy with Bluetooth. I've only occasionally tried others, but every Bluetooth-connected controller I've ever used definitely has a noticeable delay.