He told Sport Bild: "What Sebastian is doing in the red car is great advertising for formula one.
"Most fans want to see a successful Ferrari team, and Sebastian is the key to it," he added.
So far in 2017, Vettel and Mercedes' Lewis Hamilton have each won two grands prix, but Red Bull official Dr Helmut Marko sees the German driver with the advantage.
"Mercedes is driving more on the limit, while Sebastian is apparently comfortably on the podium always. The Ferrari is more consistent," he said.