if EA wanted to set it up so you could sell them for real money, with ea taking a cut, I think they could. of course they don't really want to let you do that, but even putting aside banking steam let's you sell cards for steam wallet money (which goes back to valve) and let's you buy cheap games for "free".

it's never really seemed like a limitation that needs a technical back end to fix it, it needs people to want to set it up.