I guess the main problem here with the smiles is... they may are strong, but on "our" side, or the side of the main chars here, we have no real fodder anymore. So the crew must be pretty strong, the crews around the supernovae also etc.. Surely all of them can be at a different power level, but after all, they arent fodder anymore. So if you would use the smiles against normal marines or normal pirates, they will most likely have a huge advantage cause of their powers. But these "normals" arent on the main cast side anymore, thats why the Smile-User cant really shine their way. Maybe Oda should have used some panels where the smiles crush normals anywhere.