The cards are a win-win situation.

You win because you save money. If you need this explained uh...how are you playing poker?

The stores win because they can see what things you buy together so that they can keep things in stock for you. They might even *gasp* put them closer together in the store so that you don't accidentally forget things.

Not all marketing is evil. Lots of times, it benefits both parties. It helps identify people's wants and helps companies satisfy those wants.

Very un-baller to not save money.

Although my card is in my wallet, so meh.