Looking at the screenshots (haven't seen any videos of it in action) ...
it seems the screen real estate is wasted a lot just to be able to keep the menus all lined along the circle on the right side of the phone.

Hence most of the left side of the screen is left bank in all the selection menu screens.
While it looks new and very one-hand friendly interface, I doubth how practical it will be in real life and hiow much this will catch on.

But neverthless experiments in mobile usage is better rather than sticking with the desktop paradigms as in many OS's