Why? Native offers far less privacy for BT than the web.

If you think about it, it's just hoop jumping. So your solution is Web -> AppStore -> Install -> fingerprint -> Scan For and Access all bluetooth devices forever. I'd suggest Web -> Web App Install -> accept or fingerprint -> Pair with individual bluetooth device (no scan)

The second one offers more privacy for the user and the same amount of control.

One downside: The Web App option removes a (annoying to some) gatekeeper (App Store) that can terminate apps when found to be malicious. What mechanism would you suggest to protect users from a web app that was found to be acting maliciously?

Really interesting question, first thoughts would be url and device blacklist (with an optional whitelist)… give me a couple of days I’ll give it some more thought.

I think solving this problem will be an important step towards unblocking access to some dangerous system features via the web.

But you support camera and GPS access today, right? It doesn't get much more dangerous than that, does it?

It comes down to fully informed consent. Risk of camera, or location is the obvious risk: site will see me and my surroundings, site will pinpoint my real world location. Likewise the benefit is simple to understand. So users have the info to make the choice.

With things like Bluetooth or USB the risk is subtle even to experts. We believe it’s wrong to put a choice on users that they don’t have the info to make. Not just us - if you read the Moz standards-positions on this tech, they make the same point. It’s Blink that’s the outlier.

I think saying that camera and location risks are obvious and bluetooth/USB risks are not obvious isn't quite the right distinction. There are many non-obvious risks in both.