Currently, there are many usd-based stablecoins such as, usdt, busd, usdc and maybe many others. To be honest, I used to think that crypto would completely eliminate the usd's dominance of the world economy but I was wrong, it turns out that usd is now evolving to crypto (stablecoins). What do you think, whether in the future bitcoin or other crypto can replace the role of currency in each country and leave fiat currencies such as usd, euro, yuan and others.
I'm not sure why there should be only one that accepts both fiat and cryptocurrencies. Many people continue to use the traditional method, which is fiat and, of course, far safer than crypto when dealing with large sums of money. There is no need for fiat currency to vanish in this society simply because cryptocurrency exists; they can both exist and be used by different people. Because your experiences and rewards from crypto aren't the same as those of others, it means that some people still prefer to use traditional methods over new.