Crypto market is very strange and not necessary correlated to traditional financial market, so if there will be a global crysis it's not certain that also crypto market will suffer because the biggest coins like BITCOIN and ETH could be a good alternative to $ or EUR.
That is true but the problem is not everyone has Eth and bitcoin as of this moment of 21st century 60% is bitcoiner while 40% of the household is living in normal life like working in a factory or other decsent job. Maybe if their will be a global crisis BTC and ETH will run in their own path way.