Karan Varindani:

At least in this part of the world, buying from the Mac App Store isn’t a preference. It’s the only way. There are very few apps on my Mac that haven’t been bought from the App Store, and that isn’t going to change anytime soon.

I never really considered this before. Without credit cards, it’s not really possible to purchase apps directly from the developer, so people use Gift Cards to stock up their iTunes account.