Playing the sub bar is the prime example of your skill. It lets you know:
How well you can play with no subs.
How well you can seal the deal if the opponent has no subs.
How well you can bait and make them burn their subs.
How well you can chakra dash and use your ultimate/justu's at the right moment.
I can't tell you how many times i've won a match by throwing shuriken in mid air and making someone sub on reflex. lol
Spammers are annoying. Especially the ones who know how to frame abuse. Not the classic ones like deidara. I mean the kankuro, Sasori, and Kid kakashi users. These guys can wreck you even on the defensive.
Then there's the Invul frame spammers like Masked Man. But I think they've been phased out (hopefully)