I'm signed up for the Marriott Rewards 25th Anniversary promotion, where I would earn 2500 miles after the 2nd stay and 2500 miles after the 3rd stay before May 31.

I have three hotel stays coming up prior to May 31 so I can take advantage of this promotion or continue earning Marriott Rewards Points. I figured with the rate I'll be paying, the sum of all three stays would accumulate me 15,000 MR points if I choose to earn points. Otherwise, with this promotion, I would earn about 6250 Delta Miles.

Which is the better value?

I currently have 55K points with MR and 70K miles with Delta. I could earn either one and I'd be happy. But which has a bigger bang? Thanks for any advice!