I would rephrase that say that aren't AS helpful in gameplay :) because they definitely help, if it weren't for many of my non-offensive attacks I would not have beat lance.I thought that once. I was horribly, horribly mistaken. I absolutely suck at online play. Non-offensive moves aren't too helpful in the actual game, but they rock in online play.
Non-offensive are not useless. Your friend is mistaken. Non-offensive moves are what you can get a edge in a battle. Besides, the move that all online battling teams need is Stealth Rock, which is a non-offensive move.
Also, Ninjask with Sword Dance + Speed Boost + Baton Pass = Awesome.
btw not all online teams use stealth rock
ehh its ninjask, its weak to stealth rock and only works against noobs who haven't seen it b4 so they don't know what to do
here is what ninjask is weak to
swords dance lucario (break the sub with like stone edge then extremespeed next turn b4 it can sub up again)
taunt anything
encore anything
stealthrock
trick
whirlwind
roar
i mean the amount of things ninjask cannot deal with just enourmous
though when it ends in a sweep it feels really good