There's a difference between using something and being able to copy it. Hell, Ryoma can do the moves of almost everyone on his team, but the fact that he's inexperienced in using them and doesn't have the training in specific body aspects means they're not nearly as effective as if their original players are using them. The moves may look the same, but there's a reason Inui's always around to explain that the racket head is a centimeter lower, or that the twist in the wrist isn't as sharp or something.
Jackal was able to copy the boomerang snake, does that mean he's a copycat like Kabaji. Also, Sengoku was able to copy the dunk smash, does that mean he's like Kabaji as well? =.="