~sharpen your teeth
I believe that every genre of riding adds an element to making you a more well-rounded rider. I was telling someone at TVB the other day, if you come out to Windrock and ride until you "get it," you will be a quicker cross-country rider for doing so. If you are a fit rider, and have endurance, the next step would be to work on descending and technical skills. You have far more to gain, in terms of race times, by becoming a quick descender. Because fitness comes and goes, but bike handling skills will last a lifetime.
Where else can you descend 10,000 feet, then be home for lunch? Riding steep and technical trails ~ over and over ~ will change the way you ride a bike in any situation.
However, I have no interest in racing. I am just throwing this out there to anyone and everyone. Take it or leave it.