Yeah.
This part is clearly never highlighted. And felt weird.
The whole premise during Zou, about why Kaido was after Momo and his retaniers is because he suspected they knew about the secrets of the world. And that he also wanted to know about it from Oden before executing him. YET, that shit was NEVER highlighted.
Which is clearly something Oda probably neglected.
We are yet to know why Kaidou is in all this Drama, why do he need to care about Wano and it's petty Shogun fights. He is a Pirate.
He could have easily done what he did here, anywhere else. Factories, is all he needed and cheap labour.
Oda could still highlight this, and Poneglypp could be the proper reason Kaidou choose Wano and Oden for his secrets. Bt i guess it will be revealed later on, when he's about to get defeated.