Join Date: Sep 2002
Location: Between AUS, EWR, and YTO In a little twisty maze of airline seats, all alike.. but I wanna go home with the armadillo
Programs: CO, NW, & UA forum moderator emeritus. Eurobonus Millionaire
Posts: 38,673
What your wife pays for merchant fees and what the credit card companies pay for millions of miles are two completely different things. Sure, the spread doesn't look too great, but the card companies do a LOT of volume. They charge interest, late fees, etc. and they collect all sorts of annual fees for mileage-earning cards. That's where the real money is for them.