If you're an exchange - why on earth would you give up your USD for USDT - which has never been redeemed for USD - and you can't use for anything except to BUY

If you're an exchange - why on earth would you give up your USD for USDT - which has never been redeemed for USD - and you can't use for anything except to BUY crypto - when your business is to SELL crypto?? It doesn't make any sense. What does make sense is the exchange wants to do business. No one wants to give the exchange USD. So they accept USDT. 1. Tether prints USDT then offers above market price on the exchange. 2. People put their crypto in the exchange to arbitrage the high/fake price. 3. Tether buys real bitcoins for fake printed money. 4. The exchange is happy with taking a small cut, even if it's just fake USDT money. 5. Now Tether is backed by Bitcoin - an asset they can guarantee appreciates. 6. The exchanges can use their USDT cut to buy crypto on their exchanges, too. This is risk free for Tether as long as they can keep the scheme going. It also makes complete sense to me why when Tether is printing vast sums - meme coins explode. It's easier for the exchanges to convert their USDT into meme coins. No one wants to hand over their bitcoins to a shady exchange for fake money. But they'll fork over their Shiba Inu coins for 1000x the price. Why not? Just look at the volumes on the exchanges that trade Tether and meme coins while Tether is printing money.