Well, they enhance a Pokemon's stats by the time they reach Lv. 100 & if you IV breed or EV train, you'll usually have the upper edge against an opponent who doesn't. Though it takes a long time to achieve those perfect stats. D: You should try it out sometime!
Oh, I see. Why don't we battle again once you do? My friend's been trying to get me into competitive battling, so it should be fun. 8D Do you play competitively?