In reality, it will rarely be used as a HUD. We all know with a fair degree of certainty it will be used for things like email, video, texting, etc... Sure it may have the possibility of being useful, but that is NOT what it will be used for. Just like most cellphones in cars aren't being used for GPS and traffic allerts. People these days are just too distracted while they drive. Most people barely have enough intelligence to safely pilot a vehicle to begin with. Cellphones have made things much worse. Having things distractions constantly put into your line of sight will be ever worse. While people do have rights, on the road you holding the lives of others in the balance so some of your personal freedom takes a back seat.
As a motorcyclist, I think texting while driving should get you a DUI and be pursed just as heavily.