No question is too rookie, IMHO. I'll have my fair share before too long as well.
Well, back in the day I've known people who would never, ever, use a 12-pt socket. In the end, both are essentially functionally equivalent (although, as I've learned, you'll need the 12-pt for removing the rag joint, which is the first application that demands a 12-pt socket I've ever heard of).
The reason is simply that it's far easier to strip a nut with a 12-pt socket. With a 6-pt socket it's hard to turn the wrench and actually burr the edges of the nut. With a 12-pt socket, it's a lot easier to strip the nut. They also have far weaker side walls, so they're not suited for some applications where you're really going to be cranking on a bolt or nut.
I imagine the 12-pt sockets came about to make it easier to fit the socket onto the nut, especially in tight situations and where the socket wrench is not quite aligned (you would have twice as much angle of rotation to work with).
Personally, having built several engines, I use 6-pt sockets exclusively to remove bolts and anywhere where serious torque is to be applied, like head bolts. In fact, I use impact sockets on heads, but that's a personal preference after having cracked a regular socket once. In those cases, stripping the head of the bolt would be disasterous and not worth the risk.
Otherwise, for the most part, I believe them to be equivalent.