It really doesn't make much of a difference. Because G4 itself was useless despite how much force it packs, we saw that in act 1.
I brought up G3 because all Kidd did was bodyslam Kaidou to the ground, this is the same dude that was introduced shrugging off falling into the ground from 10000 meters up in
base form. Now the ground is apparently hurting him in zoan with what visually looks like mediocre force compared to that massive fall.
No effort to show his attack's force on the surroundings either, something like this would have sufficed
Unless the ground at the top of Onigashima is made of adamantine Kidd's attack did jack all, if his level of force can damage Kaidou, Moriah could put Kaidou into a coma. Like I said if Oda wants to go with the brute force route with Kidd, atleast make an effort to make his attacks look visually impressive, there needs to be destruction on a massive scale. This is just lazy.