The hand in which you used the Wii remote made no difference. But whatever~
It's true, but the whole idea was that you were supposed be mimicing the actions the on screen character would take. Something that wasn't really fully realized until MotionPlus came out. They mirrored the game so that the hand people typically had the wii remote (sword) in matched the hand that the character on screen held it in. It's not that it was necessary for control purposes, it just made it feel more natural for the majority.