someone in the ap spoiler thread brought up that 'vin' is 'wine' in japanese french (corroborated by the fact that the ship that Sanji was on when Zeff attacked had a 2-story-tall bottle of wine as its figurehead...), and then someone else brought up 'wine steel' which was recently name-dropped and appears to be a coveted resource in the One Piece world. Dude suggested that Sanji's family might actually be storied weapons forgers with connections to the World Government, and that wine steel is the family's trademark forging material. And since Joker's out of the picture, what better way to procure new weapons than to establish close relations to premier weapons manufacturers?
(weapons... those fodder things that usually don't even matter amidst the DF-fueled conflicts of One Piece, but which Oda made a point of showing readers the impact of their dearth in the wake of Joker's defeat...)
Someone in the same thread brought up something else that I hadn't considered - Sanji's family knows that Sanji's alive, and they knew before his second bounty was issued, so either they recognized him from the ugly Duval fuckup wanted poster two years earlier, unlikely... or they were watching the streams from Punk Hazard. And who would be interested in watching something like that? Well, for one, competing weapon makers.
Makes too much sense. In the end, Big Mom gets weapons for her troops (or delicious inebriating weapons to eat), and revenge on the Straw Hats for fucking with her through the last three arcs.