I think this is a really interesting project. When I read about the helium vs hydrogen post, same as you, I started scratching things out for curiosities sake (I was more curious about how high you could reasonably go). Very exciting stuff. I've got a bunch of questions, feel free to cherry pick if you decide to respond.

How delicate do you suspect this will be? Will a bored or malicious person be able to cause harm with a laser, an air rifle with pellet or BB, or gun? In the event of a puncture what is the failure mode like? Are you worried about birds? Are you concerned about banditry? I know the last might sound silly, but you'd only really need to go to our grand-parents and great-grand-parents to find some train robbers.

I could see Hollywood making use of this for filming in remote locations. Or other situations where you need to get something heavy and oddly shaped up or over a mountain. Relief work as well where the roads aren't operable. Wouldn't surprise me if this had applications in agriculture either, if anyone is still using planes might be nicer to have an autonomous blimp instead. Maybe stuff like introducing fish to alpine lakes, if you've got good control of vertical height you could probably design a safe exit system.

Most of that is supposing that getting the blimp somewhere to then be used is easy. How is transportation of those things when not in use?