This probably comes from my background in music. Marching band members don't demonstrate their proficiency by ripping through scales at top speed, after all.
Yes, speed is going to be a component of many live competitions, particularly among the young and impressionable. In the case of music, though, we simply temper that by including aesthetics in our judgment. It is not enough to play fast, correctly, and synchronized – you must play musically as well. Musicality may require you _not_ to take a piece quickly at all!
Debate practiced at 300wpm pretty much just relegates you to the realm of competitive Rubik's Cube solvers. Which, if that's your thing, great, but it's not something you should want to highlight on your college application...