Does it matter if it's transparent alone, though? Alright, so we can verify that there are about 66.83B USDT according to coinmarketcap. Does it have a point if there can't be consensus found in a monetary policy and users have to just follow what one entity says? Sure, there's transparency of their action, but not of their arbitrary intentions. I can't do something if they decide to freeze some Ethereum addresses or inflate USDT to infinity by tomorrow morning, other than to verify it.

By the way, fun fact: Tether and Ethereum have no circulating supply completion bar. Because Tether and Ethereum are fiat.