They do for the others animals/elements, for some reason when they get to Leopard, it's left to the imagination. That particular video is such a simple subset.
I think that's meant to emphasize the fist, but again the hind legs are super important in Leopard style. A lot of the strikes are whipping techniques with cupped hands, that don't rely on upper body strength, but lower body, which makes sense given the combination of strength and quickness motifs.
Here's video of 5 Animals footwork, including Leopard technique, in southern Tiger Crane.