All easier/cheaper/better done by existing aircraft.
combine with it's massive size (and low cargo capacity), vulnerability to wind, lack of speed, fragility, etc. where is the killer application?
if you want to do surveillance, there are already a large selection of drones, all the way up to global Hawk etc.
if you want to air-lift 10 tonnes vertically, there are helicopters/tiltrotors
etc etc etc.