I do not think that cryptocurrency can completely replace fiat, but the current crisis reveals the many problems of existing systems, which in itself pushes us to use alternative methods, such as cryptocurrency.
The worse the condition of financial systems will be, the higher the likelihood of people using cryptocurrencies.
But here you need to remember that if the financial market is experiencing problems, then these same problems are also transferred to assets, and cryptocurrencies get a blow on their own, because of a market that collapses, which is not good.