It's too bad Google Glass seems to be going the way of Segways and Bluetooth headsets -- great inventions that everyone is too embarrassed to be seen with.
Bluetooth headsets... are still being used frequently? They haven't seemed to go any particular way.
I guess for patrolling long flat hallways they are nice (and faster).
It's upright, so you can be seen crossing the street by motorists, which gives it an advantage over a motorized wheel chair.
It saves energy compared to driving a car and it's use would greatly reduce traffic where cars are normally used.