That makes a lot of sense for something like a two-handed sword, or a rifle.  You'd point it with the dominent hand, and the other hand would stay attached.

The tricky stuff I was doing was partly to keep both hands together and move the prop instead, but mostly because the hands tended to crunch up due to internal rotations as they tried to stay on goal.  Creating a second body part (the "wrists" body parts) fixed that.