Yet Tether still the highest market cap stable coin.
It only has the highest market cap because iFinex print it at will, without paying any attention whatsoever to the reserves they claim to hold, a statement which has been proven repeatedly to be false. Having a large market cap says nothing about its stability, reliability, or trustworthiness.
For me, it does not matter since I only using Tether on some exchange while I am doing trading like if I am trading Bitcoin in some exchange and I want to do a BTC/USD pair trade, that's the only time I am using Tether.
Even if you are never withdrawing or transferring USDT, you are still at risk by using it. We know it isn't backed up as they claim, so the 1-to-1 peg is essentially a collective agreement between all users who are using Tether. At any point, one of the court proceedings against them could demand an independent audit or some government agency could start investigating them for money laundering, money printing, general scamming, etc. Suddenly, a sizeable chunk of users lose faith and the 1-to-1 peg is no more. Hell, at any point something as simple as too many people trying to redeem their Tether for USD could result in the same thing, essentially a bank run on Tether. As long as you hold Tether in any account or wallet, you are exposed to the risk of collapse.