Is OCZ dual channel RAM just a gimmick?

Eh, to run on dual channel, you need both matched sticks.
What OCZ does when they sell their dual channel sticks are, they come with 2x matched pairs, so you won't have anything to worry about having to purchase 2 different stick, and worry about dual channel compatibility. These stick doesn't run dual channel by itself, they need to be paired with a motherboard chipset that supports dual channel for them to run that way.