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.
We have to face the realty that the fiat that are issued by the government will never be replaced, as long as government exist so will the fiat, and for that reason all these coins that are based on USD, are nothing but stable coins that just exist to make it easier and more relatable to sue crypto, we have to take in consideration that there are a lot of people who prefer to use fiat, and there is a lot of people who invest in crypto just for the profit and don't care about its nature, so i don't think that it would be replaced.
Fiat will never be replace by any currency as long as it is backed by the government. Crypto i think is not also created to compete or reach to the point of replacing fiat because the government won't definitely allow that. A decentralized crypto will only be good as an investment, having it as a currency will make it more complicated just like what El Salvador had experienced. Although in the long run, bitcoin became a legal tender but we should not expect that it will also accepted by other country's government, unless if the government alone had already invested in crypto secretly.