This fight with Imu-Saturn will probably be the reason why Kaido's view changes to all about haki and getting stronger with it.
Kaido throughout this flashback was mainly focused on wanting to get a devil fruit and he finally gets one during this chapter, but at the same time, something must have happened that made him realize that haki is just as important or even more important than devil fruits.
And I'm going to assume that fighting against Imu-Saturn will be the reason.