I think in general in road cycling the downhill skills are still totally underestimated. Professional cyclists usually only do their efforts uphill and roll down afterwards without thinking to much about the technic. Due to safety reasons in normal traffic it’s also dangerous to push the limits. But it’s definitely possible to create training sessions with calculateable risks.
Oscar Saiz helped the Team Giant-Shimano with that in 2013. His tips and advises have been crucial for me to improve my technic in downhills. I put more attention in it since than and improved my technic same as my self confidence with it together.
Downhill training is absolutely recommendable for every ambitious cyclist. It’s not only about winning or loosing races. It’s about the energy you potentially loose as well, but also for the own safety with better skills you’re more save although you are able to go even more fast.
And in the end the speed is one fascinating part of cycling and that we all want to enjoy as save as possible.