Privacy warnings and suggestions is an awesome feature in Wasabi.
The client runs branch and bound coin selection algorithm to find an input set that's close to your desired payment amount, so that you can send a little more or less sats in a transaction that doesn't create a change output.
That means you don't have non-private coins in your wallet after the payment, and you don't need to do another coinjoin round.
Yet another blockspace savings technology in Wasabi!