If positioned in a fixed location over critical energy infrastructure , this drone is on another level.

Rockets that contain hydrogen have self-destruct, and NASA doesn't want to load a rocket with Hydrogen while astronauts are onboard on the ground; though rocket fuel hydrogen is chilled and pressurized with lots of energy.

The true cost of guarding a hydrogen blimp that's guarding the critical infrastructure? Is it as much as guarding an upriver reactor cask that's under ordinance spec?

Compared to grid scale battery farms for energy storage, would Gravitational Potential Energy and/or CAES Compressed Air Energy Storage (which are less lossy, anyway) be less of a liability if in the flight path of a slow to fixed hydrogen airship?

Aerospace-grade [hydrogen, jet fuel,] tanks are probably more impact resistant than any airship ever?

Which critical energy facilities have procedures for handling a hydrogen airship in their airspace with and without a wind event?

Gravitational Potential Energy in old mines is enough energy storage for domestic US needs FWIU, but supercapacitors or ultracapacitors may be necessary to handle renewable load spikes when the sun shines across the grid.