This isnt something that would be used enough to justify the headache of all the potential issues with this.  I just dont think its a good fit.  By all means, feel free to facilitate your own credit buying/selling using bitcoin, but I just don't ever see it being handled officially by the game itself.

Also, please refrain form posting referral links on MR.  If you are excited about a website, that should be the reason to share it, not because you can make a quick buck from our users.  I have edited the URL so that we can keep the post now sans capitalistic intent.

You can sell credits via ebay, craigslist, or swap it for sexual favors for all I care. However anything outside of the game does not come with the protection that comes from purchasing inside the game via the marketplace or via purchasing credits.  Ensure that the person you are dealing with is reputable.