USDT is most commonly exchanged for Bitcoin. You can withdraw the Bitcoin from Binance to your own wallet, so you aren't really "exchanging one IOU for another".
There are plenty of valid criticisms of USDT. Saying that it is hard to exchange 1 USDT for a dollar's worth of Bitcoin that you control is not one of them.
> You can withdraw the Bitcoin from Binance to your own wallet, so you aren't really "exchanging one IOU for another"
Until it's in your wallet, it's an IOU. And Binance has had issues with Bitcoin withdrawals, too. (Not to mention, they seem to lose their cash and coins to hackers [1] and fraudsters once a quarter.)
There is no independent, trusted marketplace where USDT trades in material volumes. And we now know that Tether previously lied about its dollar reserves. Continuing to trust them is delusional at best.
There are plenty of valid criticisms of USDT. Saying that it is hard to exchange 1 USDT for a dollar's worth of Bitcoin that you control is not one of them.