Depends on the point of view. Perhaps for the real functioning of the world economy, Fiat is no longer so necessary as before. However, for the public consciousness, traditional currencies are still of great importance.
Well it is not so necessary for a country to have fiat like take examples of countries like Venezuela where the transactions happen via the mobile phones that is the mobile money and the economy is working.
It is rather helping the government refrain from the printing of excess money that reduces the value of the currency and hence reduce the purchasing power of the currency. This situation normally leads to a high exchange rate which is not good for the economy. Besides, crypto might be the international currency only if all the countries around the world start accepting it.
You can say it into a country that has a high in economy where as adopting the innovation of technology as well, just like the country you had mentioned, but in some countries were still in crisis, I mean in third world countries fiat currency is still for them because some of them are not educated and don't have any idae about the existing evolution of technology right now.