A different point of view
I've developed a small piece of hardware with serial comms (via bluetooth, but not directly using the bluetooth API) and built a UI for it as a Chrome App. It's a great approach - I've done plenty of Swing but wanted something that's easier to distribute (check), quick to prototype (check), leverages a technology I'm familiar with (HTML/CSS/JS, check), portable across platforms (check). Frankly it's a great solution.
Except Google have announced they're dropping Chrome Apps, and there's no replacement. They're trying to push this Bluetooth API as a replacement, and if it came off it could have been a partial solution, although it's too far off for me to make use of it. The point is it's a very useful thing to have in the toolbox.
Yes, there are obvious security concerns, just as there are with DOM extensions for microphone access and videocamera access (WebRTC, already a part of many browsers), geolocation (same), and the various other things that need to do more than display a flat page, tasks which are currently confined to Flash or Applets.
But I don't see you lot bleating about that do I? What a bunch of whining jessies (last bit because I'm going to get downvoted, so I may as well deserve it)