I think another issue with the balloon would be helium leakage, having tanks and the ability to refill them on hand, fill valves etc adding weight. Not deal br

I think another issue with the balloon would be helium leakage, having tanks and the ability to refill them on hand, fill valves etc adding weight. Not deal breakers, but complicators. I think your point is more direct, although I wonder why something like this wouldn't be appropriate for surveillance of a fixed area etc.