Comment by twoodfin

Definitely not a win for consumers, who in aggregate lose out. The margins to make the system work are built into the prices you pay at the checkout.

Prices are a function of supply and demand. Higher interchange fees hit supply (costs more to produce and sell the same quantity of goods) but they also spur demand, or no merchant would accept the cards with these fees. And indeed some large merchants have (for example) excluded American Express or Discover from their available payment methods for just this reason.