Vaping took off as a cool thing without a bunch of cool people vaping in movies.

People stopped smoking in movies at the same time a lot of other smoking related things changed. Similarly smokers likely notice people smoking in movies more than non smokers.

I remember a viral twitter photo of Sophie Turner smoking a Juul while filming the last episodes of Game of Thrones

Juul changed the cultural standing of vaping and (for a very brief moment of time) made it "cool" by means of social media celebrity promotion. They were hit with pretty aggressive punishment for this by the US FDA if I'm not mistaken.