Even if Tether is backed by USD, the US government will ban it one day.
The entire purpose of Tether is to skirt around regulations when converting to fiat. When industry regulations do come, you can almost certainly bet that Tether will be targeted.
I consider the prevalence of Tether to be the greatest systemic risk to crypto. We may not even get to the regulation issue if Tether is investigated by the US government for fraudulent misrepresentation (claiming to have $2bn USD in the bank if they actually don't). I strongly believe Tether will be the cause of the next major crash–it is only a question of how it manifests itself and when
Unfortunately, posts like this get downvoted so that few ever see them. Nobody wants the party to stop, so they try to cover up any valid questions people ask and label it "FUD". Crypto sometimes feels like a religious cult where people foam at the mouth any time questions are asked. The fact is that crypto is risky and trying to hide potential issues will only make the next crash worse when it does come.