Well, yes and no. Indeed those fees do pay for cash-back and airline points and such, but most benefits-style cards have significantly higher fees than the standard 2-3%. For instance, my research last year showed that my AAdvantage Citi card was closer to 5% in total fees to the merchant. This is what is called a non-qualified rate. You can read more about it here:

http://en.wikipedia.org/wiki/Merchant_account#First_Tier_-_Q...

And an example of a processor's fee schedule here:

http://www.gotmerchant.com/merchant_fees.php

Meanwhile, my debit cards (which are almost always processed as credit since I don't like typing my PIN) still collect 2-3% and I get no benefits.