It would be unfair to give anyone an in-game advantage on the basis of their IRL financial situation. SWC is not pay-to-win, in any regard. This is why CP ships are always a bit inferior to produceable counterparts, as well.
Paying IRL money for a good in-game asset is essentially the definition of the pay-to-win principle. It's not going to be allowed, and people found doing so will be banned. Earn the credits in-game and find a buyer if you want one.
On a philosofical level, like i said, i understand the answer from the asims, Paying IRL money for a good in-game asset is for me not the definition of the pay-to-win principle. Because otherwise paying SWC to gain a cp ship would be, per your definition, also pay to win?
Pay to win, in my view, is when ascending/descending is down to 10 minutes per level when i pay. Or when my shooting downtime is lowered or when i can buy an Uber ship heftier then the common ship wich can be obtained via regular ways (I hate that too!).
I think SWC isn't pay to win, since when i donate rl monies, it won't give me (or someone who pays) an advantage over other players.
____________
Shout out to my fellow Falleen:
http://www.youtube.com/watch?v=hpiIWMWWVco
Paying for CP ships is not pay-to-win specifically because the CP ships are designed to be worse than their in-game produceable counterparts. The idea is that you can't acquire any of the best assets with IRL money, only a couple mediocre ones as a thank-you for donating. That was already addressed earlier.
You have therefore paid money that other people might not be able to as easily gain to own superior firepower and therefore have a greater chance to win conflicts.