This device appears to be a logical progression from the Segway scooter. For amputees, it would require a custom sort of saddle, but it would be great for ballroom dancing.
Not so great for climbing steps. But then, the mobility impaired and amputees already cannot do that.
Until the batteries go dead. But then, that is already a problem with power wheelchairs and mobility scooters (both of which we have at our house).