Suspension per se is not a gimmick. Doing something differently than the majority is also not - Cannondale's Lefty can trace its heritage straight back about thirty years to the Head Shok and they have had it on their XC racing bikes all along.

Suspension definitely can be gimmicky. Anything that doesn't seem like it's considered preload, frequency, or damping is where the suspicion starts for me.

For cardio racing there's a benefit and a penalty to suspension. The biggest penalty is that if properly set up for handling bumps the suspension will also operate when pedaling. Trail bikes are designed to manage this by countering it with the torque, which is called anti-squat. Most XC bikes do not. They have lockouts, and you shouldn't bother looking at their anti-squat numbers. The main benefit of suspension is supposed to be more control and thus more speed going through rough especially downhill. I'm not looking for the post right now but one guy a week or two ago mentioned it in proportion to the amount of climbing, which made some sense. A more nebulous benefit is that it may be less fatiguing, which sounds good to a non-racer, and this is where the BS puts its nose in the door - like in last week's discussion of "planing."

This is one reason the RS Ruby fork would not make my gimmick list. I don't know where they started with their development, but the huge volume spacer tells me they sent someone out with a Shock Wiz and were perhaps surprised by the result. It looks nothing like the air spring of their previous short-travel fork, which was merely a low-end MTB fork with extra travel spacers. In the other leg, the rebound is fully adjustable like any suspension fork. So there you go, it's the real thing. And they and their partners are not pushing it for every bike or every race, either.