Kirby pawnch may be amusing, but it's not a good move. >.>;
You basically copied what I said, lol. I'll add onto it, though. As I said, considering Kirby's Copy is rather situational, the most important move he can copy is a projectile or projectile reflector (Zelda). Kirby's only projectiles is his Up B, final cutter. And since it travels only across the ground and is easy to predict, it's not useful as an offensive projectile.
However, even if he gets a projectile, the person you copied off of might be able to stop it, or even use it against you. Falco's and Wolf's blasters may be some of the best projectiles for Nuetral B, but they both have reflectors. Same with Pit and a few other characters. It adds onto even more situational possibilities.
Ofcourse, if you know how to effectively use these moves, you won't have to worry about a stalemate (Falco's blaster being shot at eachother over and over, etc.) or being countered. It really takes a pro to use Kirby's Copy move to his or her advantage.