Stable coins are not same as the fiat currencies at all. USDT is an example, due to several reasons, the price of each usdt can be increased or decreased. For example, 2-3 years ago price was fallen to 0.8usd for each usdt. As far as I know, there is no chance for find an usd stable-coin which is guaranteed to to be always 1:1. The stability of the stable coins usually depends on the supply and demand and the amount of liquidity the team provided to back the price.
Leave crypto to FIAT and it opens up all kinds of KYC bunk. But sometimes one must take some profits off the table. Ride a coin up and find a safe haven as it drifts back down. Buy back in and pocket some profit. Using BTC as an example, most trust the protocol and there is a level of confidence. But what do you get when you sell your BTC for USDT??? What is there to trust?
Its more than a little un-nerving.