By encasing their arm in rock, the user can deal a powerful hardened punch against an opponent while being protected from direct contact with their target. If necessary, the weight of the rock can be increased to further increase the punch's destructive power.
In the manga, Kitsuchi's punching of Kinkaku is shown from left to right. In the episode, the punch is shown from right to left. Also, more of his rock-transformed arm was visible in the manga while in the anime, his sleeve covered it.