I agree that $200 is a slap in the face, especially for longer delays/cancellations. DL should have done staggered voucher amounts. Like: 1-2 hours, $150; 2-3 hours, $200; 3-5 hours, $300-350; 5-7 hours, $500; 7+ hours/cancellation, $700 or something like that. Disappointing.
On the other hand, SWA only gave a discounted fare sale, that's it. DL, at least, was proactive by handing out snacks, having the CEO do a video, and quickly communicative.
I guess we shall see if displaced passengers will get hotels tonight. I hope ATL won't be filled to the brim with passengers on cots.