I think crypto-currency is protection from market failures if a third world war were to happen. To be honest, I'd feel safer having my money in BTC than any financial market if a world war were to become a reality.
there have already been 5 nuclear wars, the items on the excavations emit radiation, dinosaurs became extinct for this reason
Just because there's a world war doesn't mean technology becomes extinct. I doubt we would lose access to the internet completely if a world war were to become a reality. I guess it would depend heavily on the severity of the war.
But, point is. The stock market would crash, and you'd have risks with holding your money in a bank (inability to withdraw / convert to bank notes, etc)
With Bitcoin, provided the internet is still a thing, you won't lose access to your funds.