It's a combination of both.

There are far FAR too many CC numbers available out there and when you consider the work needed to find a viable one, not to mention the legal issues resulting from this...it's pretty clear why they are so "cheap".

It's pretty comparable to the current stolen iPhone market(assuming iCloud locked), as they are basically a paperweight in that configuration, which makes them a "traders" commodity of sorts. Much like this, I've seen CC "packages" used as a sort of commodity, where the partners aren't as much interested in using the CCs, as they are merely selling them off later.