Can't speak to racing cross but I have them on my commuter cx bike (came that way). If I was racing I'd probably be on the hoods most of the time, but they're handy once in a while when commuting. My wife likes to ride on the tops a lot so I installed them myself on her bike and it was super easy. They were under $20. Most cross racers probably don't have them because they find they don't use them.