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?
... 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.