The whole point of this would be similar to that of the monowheel, where you sit right inside the wheel itself. Since there are two wheels instead of one, it saves you the trouble of balancing yourself – which is where the ‘di’ part comes in instead of just plain old ‘mono’.
EDWARD is not that special because of its form factor, as it is still susceptible to the gerbiling effect, where you as the rider will more or less rock back and forth during hard braking or fast acceleration moments. At least the team intends to minimize the effect by throwing in dynamic lateral stability and slosh control, where it can be turned on or off as required. No idea on how much it will cost though.