If you have ever experienced a gaseous fuel-air detonation, you know why. Preserving Helium isn't as critical as the sheer scale of forces involved. Trust me on this one, the risks are so severe that the costs and engineering in using Helium efficiently are worth cost considering the destructive force waiting inside a Hydrogen balloon or dirigible, etc.
In addition, I hold out hope that helium production via controlled fusion is on the horizon. That horizon may be fifty year, a hundred, or ten- but it will happen. I'll even hold out for Fusion as a power source. In the final analysis, it was clear that those guys a few years back (Pons and Fleischmann I think their names were) saw SOMETHING. Their basic idea wasn't totally crackpot, they just assumed some things were as they thought before they went public. Be it microcavitation, or even just Tomakak-esque energy dumps on a target, we will get controlled fusion within a few decades.. I'd like to see it in my lifetime, and I think that's not only possible, but likely. Then, we have Helium as a "waste product" of virtually unlimited energy..