Originally Posted by
Adelphos
Amex "renumeration" is in fact the fastest growing revenue line item for Delta in every earnings release, and is absolutely the bedrock of the Delta business model. How much of this is directly tied to SkyClub swipes/access is unknown, but you have to admit a big proportion of Delta Amex cardholders hold the card because of SkyClub access, and because they hold the card, the also spend.
I'm pretty sure the strong majority of those claims are co-branded, not vanilla. Hell, on the purchase of a flight ticket alone, Delta would probably save more in transaction fees on a Reserve cardholder than they would make on a lounge visit.
There's a reason every large company and their mother has their own co-branded card. The perks are limitless and far better than external cards would give.