This is what I'm poking at, it sucks ass when you slip a pedal. I ride a lot of uphill so having clips or locking shoes is nice because at the bottom of each stroke you get more power since you can actually lift the pedals.
For mostly downhill I think what your going after is better.
I think that's the reason....a lot of downhill and freeride with jumps. We obviously have to go up hill, but it is more of a means to an end so we can go back down the trail or hit the jump line again.