My personal opinion is that the non-DL Amex cards (e.g. Gold, Platinum) have always been better than the Delta cards UNLESS (1) you want a year of free checked bags and the 15% award discount for $99 (DL Gold Card), which can make a lot of sense on Delta due to the 2500 mile compensation for the 20 minute guarantee, (2) you are an enfranchised Delta customer with a reason to get the companion cert(s), MQD waiver, and MQM boosts, (3) you value Delta lounge access and the other Reserve perks. Only the second group should spend money on their cards.

The 10:1 (Reserve) or 20:1 (Platinum) spend to MQD ratio and the increased MQD thresholds will change the math for many people in group 2 and tip them over to the DL cards not being worth it. Inertia will probably cause many customers to keep the cards for a time, but I expect we will see the road warriors abandon the DL Reserve with the Sky Club limitations.

I'll probably pick up a DL Gold card at some point when they run a large sign-up bonus, because I don't expect to make FO in 2025 and plan to be a free agent that skews AA.