Digital advertising agencies are special in a sense that game dev isn't really other domain for those. If you do your tech inhouse, its likely you'll have people capable of gamedev, be it iOS/Unity/Unreal/Defold/HTML5 or (much less these days) Flash.
They're not digital advertising in the traditional sense, although they do a bit of that. They're interactive stuff, some physical stuff. And some games and software, which is why they had Filipe on staff when he tendered his resignation to start work on KSP, setting the whole thing in motion.