I wouldn't bother with a CKC registry because:
(a) I don't want to give money to an organization that essentially exists to legitimize puppy mills;
(b) as far as I know, they don't have any sports or trials, so registering my dog with that organization wouldn't help me actually do anything, whereas if I pay that same $25 to register my dog with a sport organization then I can do stuff and have fun;
(c) it's not a "real" breed registry so registering my dog doesn't help with breeding it or registering the progeny (plus I probably wouldn't want to breed such a dog anyway).
Curiosity is a legitimate factor, but speaking only for myself and only in the hypothetical, I would rather not give $25 to an unethical organization (and in my opinion the CKC is an unethical org) for a very probably fake pedigree when I could just make up my own fake pedigree for fun.
But I can certainly understand why you might decide differently, since curiosity IS an incredibly compelling force!
ARCHMX TDCH Pongu the Insane, CD-C, RE, RL1X6, RL2X5, RL3X2 (GSD mix, b. Apr 2010)
Crookytail the Tigerwuff, RL1, ITD (Akita mix, b. Jan 2011)