I admit it's cool but..
if you want to talk to someone you take it off and hold it to your ear or you just hold your wrist up to your ear like some sort of tool? Suppose the bluetooth headset is the only option but never really get along with those, prefer a wired handsfree, which i suppose you could snake up your shirt sleeve.
Also if we're going to strictly hold to the rules you'd have to take it off to go fill the car up at the petrol station.
Seems cool but i bet the reality falls far short of the expectation