"The trouble with having an open mind, of course, is that people will insist on coming along and trying to put things in it."
Terry Pratchet, Diggers
I made a point to use the AR (Augmented Reality) functionality on my Google Maps mobile app during my most recent trip to Tokyo, Japan. And I was pleasantly surprised at how well it actually worked for me, even though it is still in the Alpha stage (yes, not even Beta).
While navigating through the mobile, it made sense for me to hold it up in front of me - like you were recording a video for example. But it does not feel natural at all, and a little clumsy and clunky. At times when I did put the mobile down to rest my arms, the "live" arrows seem to disappear or take some time to re-calibrate.
The other minor annoyance I had was the constant safety warning that kept popping up on the screen, and at times, blocking parts of the map that I needed at that point.
Overall, I would give the experience a pass. But it definitely makes more sense to use this via a Google Glass, or an AR capable glasses/headset.
I can see a potential here for third party devices though, to allow a user to "transfer" and project the AR elements from the mobile app, to their everyday standard non-AR glasses.