On short bouy type courses, I think less is more, get your head out of the boat, look for the next shift, puff, etc. rather than looking at your instruments which will only show you what just happened, not what is about to happen...

On a longer course, where you cannot eyeball the A mark or on an empty horizon where you cannot see the shore to notice a slow headder, a compass is essential, and speed is nice, but you may spend too much time watching the numbers vs. watching for the next shift.

This sport is a lot like flying airplanes, you have to keep your head on a swivel and be scanning everything, all the time, gliders now have an audio Vertical Velocity Indicator so the pilot can hear a tone which changes from low to high pitch as he gets into or out of lift, so he can keep his eyes outside looking for...other gliders!

Sure I would love to have such a system on board but I'm not sure it would make me a whole lot faster, the really fast guys can see the shifts coming and tack before they get there. If you wait for your compass to tell you, well...you're late.