Doesn't it convert a liquid asset into a much less liquid one, given that tether is far less widely accepted than USD? If I have a million dollars in greenbacks

Doesn't it convert a liquid asset into a much less liquid one, given that tether is far less widely accepted than USD? If I have a million dollars in greenbacks, I can use them for almost any transaction I like. If I have a million tethers, I'm not sure I can do much with them except exchange them for other similarly-illiquid "tokens" via a few variously-reputable exchanges.