I can't say I know all of the possible attack vectors of Bluetooth, but it's probably easier to intercept that and it would be to read the QR codes on two devices from a distance.

In the vast majority of practice, I'm not sure the difference would be that great.

As to scanning the QR, If you're using your Jade statelessly, then you will have to scan it every time. But if you're storing your seed in the jade (encrypted), then you will only need the pin.