Codes for games if you want to be picky, not "PSN Codes".
It means they can bundle or discount or do whatever to individual titles.
Buying PSN dollars on special is all well and good, but if the game prices are still stupid it doesn't help a lot.
Well this isn't something new to me.
GAME have it for PSN:
http://www.game.co.uk/en/games/playstation-network/?cm_sp=topnav-_-PS3-_-PSNLogo
For Xbox Live:
http://www.game.co.uk/en/games/xbox-live/?cm_sp=topnav-_-x360-_-XboxLiveLogo
And Nintendo's eShop:
http://www.game.co.uk/en/games/nintendo-eshop/?cm_sp=topnav-_-Wiiu-_-eShopLogo
All at discounted prices compared to direct from the marketplaces. Deals on the odd occasion (they had one where if you prebuy the download of Pokémon X & Y, you got the download of Pokédex 3D Pro) and so forth.
Have to say I'm surprised if this is the first time the US has anything like it.