I am certain we have satellites that can see essentially every square inch of the Earth. But not "directly" overhead every minute of the day or night. And for sure, there could be advantages to having a camera "directly" overhead, as opposed to being off to the side.
Also, while we have imaging technologies and devices that can "see" in any weather, the best imagery is still on cloudless, sunny days. Or when the camera can be "flown" below the cloud ceiling without the risk of being shot down.
And if these mach-5 drones can drop smart-bombs or fire missiles or rockets, that opens up an entire different realm of potential uses.
Of course much also depends on their range. While this appears to be an Air Force project, I have no doubts the Navy is keeping a close, first-hand watch on it too.
