Kaido believes that with luffy, zoro and law, he can conquer the world. Shows how much kaido who is strongest in the verse respect their strength.
I hope and pray that oda throws a curveball and make luffy fall to kaido and bring an end to act 3. A tragedy needs to happen in this arc, right now there isnt a feeling of despair or urgency of defeating him. Its just like he's the big bad guy that needs to be taken care of, even that im not sure, he didnt even killed the scabbards when he had the chance.