Cool way for a hundred Marines to launch a surprise attack on an enemy - though I’m sure the DoD has a superior version of this already.
I think you have to learn how to fly it and position and balance yourself. So those Marines would be specially trained. But it is a very interesting concept.
But take 4 of these devices and install on each corner of a platform, and you have a flying drone that possibly anyone can fly with carrying a lot of weight.
You could also leap from the tops of buildings.
Or law enforcement personnel can hover above crowds.
Yes, no one will hear 200 jet engines coming at them at 90mph.