"On that date, the law firm said, it is "confident" Tether had more money in the bank than tokens in circulation (specifically, $2.55 billion of U.S. dollar reserves, held at two separate institutions, to cover $2.54 billion USDT). But the report says nothing about the level of collateralization on any date before or since. 

In other words, it doesn't purport to show that USDT has been consistently secured over time – or that it is fully backed today."

I think it is good enough.