From my own riding, watching my kids learning their bike skills, and coaching other kids this is indeed a really important point.
The Professional Mountain Bike Instructor* training focuses on six essential skills that are required for mountain biking, and the implementation of those skills just get better and better the higher the level of riding. Our coach showed us a video of the Yeti Enduro team – Richie Rude et al – weaving through cones as part of their training, just like the eight year olds I coach… but at warp speed down a ridiculously steep fire trail.
And btw, hardtail lines are the best lines.
*I am in no way professional