If you consider the USD a shitcoin, which most of us do, then your opinion is entirely valid.
But the USD is a shitcoin spendable in most of the world.
Discussion
The only benefit of USDT in my opinion is you can swap in and out without using a KYC centralized exchanges bypassing the need for “off ramps” for spending etc. if USDT was widely accepted as payment there might be some benefit in that regard. Or as a hedge at the peak of a bull market when the top blows off. Again without having to go through centralized exchanges.
Most of the traps and choke points are on and off ramps so anyway to avoid these is beneficial.