Does the whole Virtual Desktop trick really perform well enough to play games without frame loss and disconfort? I have my doubts, because otherwise they'd market it as a wireless-streaming headset.

I took one of the mesh routers in my house, plugged my pc in and I can honestly say that the wireless experience is insanely great. I can't feel a difference between wireless quest 2 and my rift (apart from being tethered of course). The reason why facebook doesn't market it as a wireless streaming headset is that the wifi setups of different people vary a lot. That's why OP said he found the streaming to not be the same quality as tethered vr while I have maxed out all streaming settings and find it to be the same.