Nintendo revealed a little bit more about Punch-Out for Wii:

The motion-sensitive controls of the Wii console mean that when players throw punches, Little Mac throws punches as well. Additionally, you can control hooks and jabs by combining motion control with control-stick movement. The motion-sensing Wii Remote and Nunchuk controllers turn real-life swings into on-screen punches, so anyone can play. The game can also be played with classic NES-style controls by turning the Wii Remote sideways.

I’d like to think my clout as a blogger forced Nintendo to include this option, but it’s more likely they did it because it just makes sense.