You saved me from being longwinded about it. Exactly this. Also, because WiaB exists, SG doesn't have to explain the backstory, people can find out, Ocean doesn't need to waste half the story narrative telling the past, outlining relations and connections. Ocean shows Emilio in WiaB, suddenly we know what allegiances Emilio might have. Noji mentions Scarlet, she don't need to go into exposition on who Scarlet is. Katie appears, and there is so little explanation of the Zanes, just Willi's proclivities. It also allows an incredibly detailed backstory.
I still think of the two as parallel timelines in the one story, alternating chapters of the same book (like Steve Erikson does) giving alternating perspectives that build up to a conclusion.
It just takes longer, but I personally think it'll be worth it.