[Scion9066]

Or things like Web USB start getting used to provide useful features without needing to install whole apps, like mouse/keyboard dongle pairing, phone OS flashing, etc.

As far as fingerprinting/tracking goes, I have never seen a random site prompt for these features, only apps where it makes sense.

[lxgr]

Same here, so I'm really not sure why you're getting downvoted. I'd be really curious to hear any examples of sites doing that!