MQMs roll over each year so even if you don't make status, you'd keep them. To a Delta flyer this is an attractive deal -- I know people who paid $495 for 5k MQMs directly from Delta last year in order to hit GM status.
The bloggers on average seem to value Delta MQMs at around 3 cents each, which would price the value of this offer at around $150. I value them at 2 cents because I'm a bit more conservative, but the rollover benefit that Delta provides is a material sweetener.