Originally Posted by
xliioper
In terms of marketing materials, it has been referred to as part of Main Cabin experience. However, I wouldn't assume they are necessarily following the convention here. It seems a bit pointless just to add a separate tie-breaker just for the small handful of domestic PS flights. It would be pretty straightfoward to do an experiment in the new year (with refundable fares) and see were people rank based on purchased MC, C+, fare classes, MM status, etc.
Delta is inconsistent in some of their marketing materials, so for different purposes Comfort+ has more or fewer traits of a different "Cabin" than Main Cabin. Delta tells the governments of the world that Comfort+ is not a different cabin (marketing it as an "experience" in the Main Cabin), because if it was they would have to to pay downgrade compensation under laws like EC261 when they move people from Comfort+ to Main Cabin.
However, my gut tells me that this change is intended to move paid Comfort+ up above Main Cabin in the upgrade priority for two reasons: (1) Delta wins if they can convince some PM/DM travelers that currently book Main Cabin and get the instant upgrade to Comfort+ to pay for Comfort+ instead (likely because it's within their corporate policy) and (2) DL tries to find value-adds to differentiate Comfort+ from Main Cabin, and enhanced upgrade priority is a value-add.