There is no direct difference, but indirectly yes! If the value of the cryptocurrency goes up, the value of fiat currency that is USD will go down. In simpler terms, you could buy 1 BTC for $40  years ago and now you have to pay $15k+ to buy 1 BTC. As long as your BTC-USDT/USD is concerned, you can't buy USD from a digital exchange. You can either convert it or liquidate it.