USDT is stable but transaction fees are still a little high, so why pay $1 on the Ethereum blockchain or TORN when I can do the same transaction with cheaper fees using LTC Doge XRP and a lot of coins that offer very low fees.
Transactions on the likes of BNB, Solana, and Tron are sub $1, and the fact that you wouldn't need to rush things and do the transactions immediately because the price of LTC/DOGE/XRP can move quickly knowing how volatile this market is. With stablecoin transfers you can just chill.