As XC racers, we’re pretty adapted to riding with our seat up, but could we gain more with a dropper? I tested my Orbea Oiz with a Fox dropper on a twisty, three minute descent at home. The time difference was only one second, not that significant, until you compare my heart rates, 10 beats lower with the dropper. I would call that a difference maker in racing.
I think in a few years time it could actually become standard, because you have a lot more room to move your body in downhill sections.
It so much better, more comfy, and fun! And I think that having fun is the biggest advantage of using dropper seatpost.