DL has also leaves zero room for irrops. So when an agent types furiously for 10 minutes and makes countless calls to put you on another flight in irrops (as their “rescue” flights for irrops seem to always take 1-2 days), it’s usually a seat request and left to the mercy of the pilots do they give up their D1 crew rest seat or no, which you find out at the very last moment at the gate. I haven’t seen DL actually offer anything to D1 pax in such oversold/irrops situations.