[gojomo]

The illusion that the display is a window into another parallel 3D world might prove very useful once developers & users know how to exploit it.

Tilting the phone to see 'under' the current foreground might be a way to show next-messages, pending-notifications, etc.

Add a backside display, and perhaps you'd flip the phone for 'details' - and the eye-tracking ensures that usually, only one side is powered at a time.

Or what if each side of a telepresence-connection is being live-mapped with technology like:

https://www.youtube.com/watch?v=Ghgbycqb92c

Then, even without a head-worn VR display, your handheld phone/tablet can serve as a roaming-camera into the remote space.