Really cant be bothered with it, I guess it can be useful for routes, but other than that it bores me, and unless you are racing then I dont see the point, especially when used with a power meter, and people seeing how they have improved then good luck to you, why are you trying to measure your improvement against yourself, so you beat yourself? well what do you win?
soooo boring and the people going on about it are bores.
Maybe if these people had more interest in how their friends are getting on and focus on helping others to enjoy their riding, its just an awful state of mind to be so obsessed with yourself unless you are a pro and its your job to be measured.