I was not making a judgement about whether or not there's a difference between a single balloon and a drone swarm (there is), but addressing the comment:

And also, in typical neo-luddite fashion, I'm fearful for the surveillance applications of this device. Even if staying airborne isn't eventually completely free (eternal flight) with this system, the ability to stay up for 9 hours at a time on a few Li-Ion cells opens up a world of possibilities, not all of which are great.