What specific benefits are you trying to get out of Platinum status that it's worth chasing 6,000 MQDs to you, either in direct spend on DL, partner flight spend, Co-branded CC spend, MQDs for Delta Stays/Delta Vacations, or via manufactured spend?

I'm usually one to defend chasing status to a large degree but I can't say PM is worth chasing 6K in MQDs for unless you close a significant portion of that gap through co-branded CC spend that's for expenses you expected to make (or maybe get some of the MQDs through opening an additional qualifying DL AmEx that comes with a 2500 MQD head-start).

Otherwise I have to say the money you'd be spending chasing PM status could buy a lot of C+ or F upgrades (and the F upgrades are going to be more and more rare anyway).