Are Trailers for Trailers a Good Thing?

A few days aog Jurassic World droped a short 30 second clip of very brief things from the movie. All it shows is just people and nothing special. But I am not here to talk about the trailer itself I am going to talk about why I don't like when studios release trailers for trailers to get hype up for their official trailer. A trailers job is to give you little bit about the story and to exite us about the movie as a whole. I dont see the point of wasting time to get out a trailer that shows us next to nothing just to get us hyped up for the thing that is supposed to hype us up for the movie. I just think it is silly to waste your money and the editors time to put out something people don't even want.