Our wallet address needs to be connected to the exchange in order to make transactions and that requires our approval, I don't think you need to worry too much because our wallets are not always automatically connected
When you do trade on uniswap it sends 2 txn, 1 for approval and another for swap EXCEPT if we swap ether because ether need not approval thus it is safe as it need one txn only. Metamask connected or disconnected, it has no role after sending approval txn.
yes you say, but it needs to be emphasized that the agreement is not a swap agreement, not a transfer agreement at will without us agreeing to it, it still needs a second agreement to be done, and when we close the browser, the connection will automatically be lost?
You are right it is not swap txn where we chose what we need in return in exchange of usdt.
But it is withdrawal approval txn where we allow that address to withdraw that much token from our wallet. What we assume is it execute only if we send swap txn but no. Approval itself means that contract can withdraw that much usdt. In normal case we allow it via 2nd txn but in case of bug or hack, hacker would not send tokens in return, they just withdraw usdt. read article.