It depends on where the crisis took place for instance if it is in a developed country, we can say bitcoin can be a saving grace but in a developing country like mine, I don't pray for any because if it happens to hold bitcoin can't have any advantage over fiat other than you are sure your investment is secure.
Holding BTC doesn't have any advantage in a time of severe crisis, it does not matter the place the crisis took place, it could be in the United States or in Kenya, whether a developed or an underdeveloped country; people just do not think about BTC when they have lost family, friends, relatives, neighbours, etc. In a time of crisis the thing to do is to worry about those who were affected in the disaster, and not to think about the advantage of holding BTC. Fiat is even easier to spend than BTC, and it may have more advantage to have than BTC in a time of crisis.