As Oda has made very clear the Wano Arc is about more then just beating the Yonko and freeing Wano. It’s about advancing the story of the Void Century, the Rocks Pirates, God Valley Incident, Ancient Weapons etc.
As such, when it comes to the Straw Hats, no one is more influential to this story then Nico Robin given her unique translation skills and her knowledge of the One Piece World’s history as well as the perspective she gained working with Monkey D. Dragon. Duke Dogstrom even made mention of this on Zou for those who remember, and I’m sure Oda included this for a very specific reason.
Big Mom & Kaido probably recognize that conquering the world is through Laugh Tale, and between them they have two Road Poneglyphs. Either through Kanjuro, Robin, Momonosuske, or finding Zou via Vivre Card they can get access to the 3rd Road Poneglyph leaving only one Poneglyph to go.
Given that Nico Robin is literally being handed to them on a silver platter, I can’t see how they would ignore the opportunity to capture her her and find a way towards Laugh Tale.
As such I think the strategy on the behalf of the Yonko will be to actually capture her & pair her up with Oden’s children to accomplish something much larger then just conquering Wano & beating the Alliance and this will drive alot of the immediate story & larger story forward.
Even if Kaido and Big Mom were to be defeated by the end of the arc, to me it would only be through the intervention of a very powerful 3rd party (CP0? Blackbeard?) whom would share a similar interest in Nico Robin, and as such their strategy towards Robin would still end up driving alot of the story.
What are your thoughts about the role Robin will play?