If USDT suddenly crashes like UST, it will have a huge effect on the market as USDT occupies a large part of the market. And many may suffer greatly. USDT is trusted by many people and many hold huge money through usdt. If i say my personal thing i use usdt but don't hold all my money in usdt. I hold about 2-5% of my total assets in crypto and keep 25-30% of that in USDT from this budget and rest is other coins. So even if USDT crashes, I have no chance of major losses.
Still can't forget with suddenly crashes from USTC stable coins with Terra Luna network until right now because my position staking that stable coins and loss almost 30%, for the future have been selective when staking or holding stable coins due many kinds network launch their stable coins. I think most trusted stable coins are USDT and BUSD with Binance exchange back up and not interested with holding other kinds of stable coins worry will follow what happen on UST.
Not recommended hold assets in USDT or other stable coins because not profitable yet than holding altcoin or bitcoin, I think with low profit earn as short or long term holding better put our assets in Bitcoin and hold few percent in Stable coins.