Ask your self which kind of money still can be used after this circumstances:
-fire
-natural disasters
-revolutions
-financial crisis
-war (including electro magnetic pulse and destroyed infrastructure)
-death
-several generations
If you're asking what'll be used after total upheaval in the world, including destruction of our infrastructure, it sure as hell won't be bitcoins. It might be gold. Might be iron. Certainly, gold has thousands of years of history of being used without modern infrastructure.