Its a good question though. The real value of any navigational device is can it save you when to poo hits the fan? I'd hate to be without map and compass then. But in a race, if you get to that stage, the race is lost and its all about safety.
For racing, a pre-programmed route with audible prompts would help with any nadgery navigational choices without having to slow down to faff with map and compass. Is that 'cheating'?