Well if you use sunglasses and pull out your phone to take pics, videos and see the time ... using the glasses to do all those things (even without having your phone on you) makes a lot more sense (quicker and easier).
Quicker & easier isn't the end all be all–having distracting tech on my face is likely a net drag on my happiness, focus; given how distracting smartphones already are. It would have to be _so_ good that I'm willing to live with that extreme downside.
