Target has changed their policy about Red Card working on Game Cards recently, so now you can get 5% Off various gift cards in store and online along with PSN, Eshop, and Xbox cards. It used to only work on a few cards, like the Disney gift cards.
It has always been this way, as others said what was changed was the ability to buy other gift cards with gift cards. But hey, for those that are just learning this works, surprise! It does come in handy when they have their occasional B1G1 10% off or whatever.