Have you seen someone wearing one of these? Holy crap! All you users of these ugly headsets have gone from dorking out your belts to dorking out your face and head. I understand that these things have to pack a battery and bluetooth radio into the device, but someone has to be able to design something that looks even remotely like it's supposed to fit on your face.
Bluetooth, in my mind, is very useful for data tethering and some of the speakerphone devices for your car and desk are pretty cool. Additionally, I think that some of the hardwire or factory-/dealer-installed bluetooth are pretty cool.
I can say that you won't see me wearing a bluetooth headset any time soon.