As usual, the first reaction is to ban what you don't understand. The bottom line is, it's being banned while driving basically because "people can do whatever they want with it" (i.e. there's nothing stopping them from watching videos while driving instead of just wearing it so you can say "take a picture" when you see something you want to capture)
Google Glass does not obstruct your entire field of vision, either.
Fucking fearful, overbearing, reactionary Yanks. I'll bet the judge they get to approve the new law is so old he's got cobwebs on his arse.
Ban the behaviour, not the device or act. For example, it's not specifically illegal to eat while driving. Common sense dictates that you wouldn't eat a big messy two handed meal that's going to take your attention, while trying to steer with your knees. If you do, well there are charges for "distracted driving" that don't cover a specific act.