It is great as long as they are actually sticking to short dated US t-bills. They've just been super sketchy about if they are or are not in the past. Personally I think they're fine. The absolute worst case there's a run and depositors only get back like 75 cents on the dollar. Which is way better than most places that people park crypto.
My amateur theory is that Tether could have imploded for most of its existence, but now there’s a real chance that they have been (or will be) able to bluff their way to solvency.