I think it's safer, faster, and the country can save on the cost of printing their own country's fiat currency. we all know that the costs a country has to spend on printing their currency are very expensive, and cryptocurrency is the solution...
It is not that shallow reasoning, when the states convert to cryptocurrency then everything will change, everything in the financial transaction will change, and therefore the price will raise because of the demand in the market there are also lots of alts to be released.