We can only keep faith with USDT having actual USD value to back it up with, though it looks very fishy time to time, but the company has proved in the audits about the usd backing there USDT.
I personally, prefer staying in satoshis rather than USDT, however, during the collapse of entire cryptospace, I sometime convert my satoshis in USDT and then turn back them in Satoshis when the prices are real low.
I always have the same fear but eventually till now I did made decent profits by trading BTC-USDT and retrading it back to BTC.