I don't think using a display when walking around is a good idea or even just safe to do. On the other hand, I think it makes perfect sense to have something a

I don't think using a display when walking around is a good idea or even just safe to do. On the other hand, I think it makes perfect sense to have something a like a fighter jet HUD - important information in static places (time/location/notification status/etc.) with possibly some highlights (showing where is the next bus in AR, annotating things when you look at them, seamless translation of text, etc.).