You should also consider the huge advantage that an airship has above anything else - loiter time. In WW2 the US Navy, and in WW1 the Royal Navy used them really effectively as submarine hunters - the ability to chase a sub for days on end was pretty priceless there.
There have been a few recent successes using airships for science work - following pods of wales, measurements over the top of a rain forest, that sort of thing.
If a commercial airship project has a future, it's got surely to be exploiting that. Again, these chaps seem to have a sensible idea there.