Re: the credd theory above
No. Why would they care if there are Credd's flooding the market? those are all bought and paid for subs. You buy 6 months of credd's and sell them off rather than buying the cheaper 6 month sub? Ok? they made more money. They're GLAD you did that.
That's the real reason it's more - people will buy them because it's safe and secure gold selling (I could still get a direct line from someone for cheaper, but it's a hassle and there are trust issues, etc), the market will dictate the in-game value, and the cost being higher out of game makes Carbine more money.
Example: My intention is to play the game with Credd. I'm hardcore in MMOs, and I'll make the money. Whatever market value is, I'll figure out a way to have it every month no problem. The fact that it's 5 dollars more? Makes 0 difference to me. The person selling the CREDD is simply looking to convert RL cash into in-game currency. The fact that it costs more can be reflected in the market value - their return on investment is no different. It's all upside for Carbine.
Do I think it SHOULD be 20 bucks? No, becuase I think the impression people get is that it's mildly sleazy, when realistically it makes no difference to anyone, but again: Matters not to either the buyer or the seller, so who cares.