Is it really that great for the doomsday scenario? If a person is in the same room and Bluetooth works, I don't need any special app for sharing files. If it is remote, I don't see how spawning a wide area mesh network should be even possible with the most recent generation of smartphones. The sending power is just too small.

That's a cool thing but ... if I'm close enough to use Bluetooth do I need to be wasting potentially precious battery chatting with someone nearby?

As for it's mesh features I also question how reliable (if at all) that would be in such a scenario.