Yes, fiat are not that affected but nowadays, cryptocurrencies are much necessary and being prioritized by people because of its improvement in advertisement. As the market have no activities-related to cryptocurrency, bitcoins will really become less useful in transactions instead people will just hold it and wait for the increase in its price.
People are really knowledgeable and intelligent enough depending on the situation where they will benefit their assets completely. In terms of government, I know that they are only prioritizing the use of fiat because most of the people in the community are still ignorant about how market moves and they don't care about the recession, they just earn and spend their money and that's it.
As they said it, it is the most liquid asset. Without the push of the government, people will continue to use fiat since it is the natural way of getting their essentials or their necesseities in their lives. You could use bitcoin or other currencies but the easiest one is by paying them fiat. When it comes to taxes, it is already added to it when you buy it, there is no way you could run from it unless it is income taxation of some sorts where the people themselves calculate the taxes they needed to pay.