The more I think about this, the more I'm fine with it, with some provisions:
* Cash-bought stuff should be segregated, and cash should never be exchangeable for credits.
* To that end, something bought with cash can only be sold back for cash, but because refunds of real cash should never be allowed, that cash would only be good towards buying something else with cash... and because cash and credits shouldn't mix, if you don't have enough cash to buy the thing you're trading in for you'll need to break out your credit card to complete the purchase.
* Seriously, no pumping credits into cash ships. Cash bought ships should be outfitted with cash.
* Cash bought ships should be repaired and rebought with cash.
* Cash bought equipment should not be mountable on credit bought ships.
Some may think this moves further towards pay to win, and maybe that's true. That argument isn't of interest to me. The important element in this game is risk, what little there is of it, so if your wallet is going to be In The Game, so to speak, then your wallet needs to be bearing the risk.
Of course there will still be some cash/credit cross over, in the sense that you can buy yourself a nice trading rig with cash and earn a ton of credits. I'm okay with that. It seems to me that after a big cash outlay if you are able in this way to transition away from your cash bought stuff to credit bought stuff, then that's a positive outcome for the game.