On the other hand, as long as those communication islands don't reconnect, all those double-spent BTC will be just as good/bad as homemade dollar bills. Bitcoi

On the other hand, as long as those communication islands don't reconnect, all those double-spent BTC will be just as good/bad as homemade dollar bills. Bitcoin might be postapocalyptically valuable if the apocalypse in question has hyperinflation at its core, but in a scenario without that it will be inferior even to vintage paper money. The true availability of BTC within a given community is just too much of an uncertainty. What could be a sizable fraction of the amount in active circulation one day could be completely devalued due some early adopter backup going live a day later.