Perhaps, if people are just trying to generate credits from the cartel market then are the ship parts the best CC to credit ratio? I don't personally know as I have never looked into that.
Probably not the best direct CC to Credit, since other items will sell for millions. But, definitely the best way to go about it, since you can buy the ship upgrades specifically without relying on RNG and Cartel Packs for the higher value items.
Actually by allowing them to be obtained without RNG, and without making them BoP, it's a pretty good credit farm for people who can afford to turn real money into game money.