Personally, I dislike even getting the Smash Ball. I dislike using it, I feel guilty. Do you feel like you've earned the easy kills you get via a Smash Ball? 'Cause I sure don't. Depending on character, situation, level, opponents, and luck, I can get exorbitant amounts of KOs from a single Smash Ball in certain instances. And for what? Because I happened to beat someone to a floating, shiny ball? 'Cause I happened to be jigglypuff on a small stage and was able to chase it off the level incredibly easily? 'Cause I was Lucas or Snake and hit it with a guided projectile from a safe distance? Because it spawned right in front of me while my opponent was off the stage?
Even if I fought tooth and nail for that Smash Ball, how could any 10 second scramble for a shiny orb possibly merit 4 kills for me, given a small stage and a landmaster? How could that short struggle, no matter how bitter, possibly merit the potential level of destruction I can now reap?
I feel much better, much more assured about myself as a player, much more reasserted of my own abilities, to kill my friends without Smash Balls.
Edit: Just to be clear on my own situation, I frequently play with Smash Balls, and many other items, on. Most of my Casual friends who I play regularly with prefer things that way, and I don't mind enough to argue the point. I have a more Competitive mindset, though, and I have some limited Competitive experience, as well--enough to know which I prefer.