I usually used USDT in pair with Bitcoin when trading, and even use it for altcoins. I would it was safe to use this base on my experience. But, this never means that it all be the same experience with others, not even to say the use of USDT will assure safety because it all depends on the trader.
What I can just say, it doesn't matter what stablecoin you used in trading as the most important is that you know how to do an exit when the situation turns difficult, stop-loss is really helpful.