Because one uses blades - cutting attacks -, while the other uses blunt force damage.
Kaido gets more or less significantly damaged only with either blunt force damage + internal destro CoA/CoC or CoA/CoC infused blades.
		
	Kaido gets more or less significantly damaged only with either blunt force damage + internal destro CoA/CoC or CoA/CoC infused blades.
so I don’t know where you got this idea that Kaido some kind of Luffy type tank… no… Kaido is completely immune to all damage except internal damage and advanced armament
 
				 
 
		 
 
		 
 
		

 
 
		 
 
		 
 
		 
 
		
 
 
		 
 
		