Thanks for sharing, I wasn't aware that these airship as cell-tower tests had advanced that far already. Really seems like the better alternative to something like Starlink.

Station keeping at that altitude is tricky. Wind is really strong up there, but fortunately there are no clouds - seasons accounted for, every day gives the same amount of solar power. And it's really cold.

Regardless, going there is economically really attractive, compared to throwing a satellite into orbit.

You forget the two most important parts.

1. A lighter than air vehicle you directly have control over is far more resilient to attack, difficult to pin down the location of, and maintainable than a satellite either orbitting the earth in predictable trajectories that place them periodically completely out of your view or sitting there like sitting ducks in geostationary orbit, either way shooting them down is a difficult but entirely soft problem for the major aerospace powers of the earth.

2. The X-37b cannot fly up to your communications relay lighter than air vehicle while it is sitting in a lonely dark void with no one watching and reach into the insides and start fiddling.... Through the use of aerobraking the X-37b can easily move in entirely unpredictable ways, so this is just an open question hanging out there in space for satellite based infrastructure.