On the other hand, maybe some people actually like the pinterest pages in results, and i'm the weird one... who knows.
It isn't just you! I suspect that for certain people it's easy for them to get distracted there though.
I've seen some data on this, and that data was inconclusive. Sometimes it seems to work, sometimes it seems to be counter-productive, sometimes nothing happens. It's hard to truly test things in isolation, and maybe their methods were shit, but I don't think it really does anything, or maybe Google has solid ways to detect anomalies and ignore them.
I don't think that if a user stays a short time necessarily means the content is garbage. It might also mean that the user found directly what he was looking for, such as the answer to the question.
It might even mean the page is very good as it is clear and provides the answer and does not have other click-bait type content.
Landing on a bad page, might require you to read and browse around and maybe after a while figure out it's garbage or you get distracted by some "interesting", but unrelated articles. But if the search engine would rank it high because of this then that would be wrong.
But looking at my kids, looking directly at the info box and considering the answer as given by God, I suppose I am an exception.
But Google definitely tracks such short clicks and considers them a bad signal, very important in ranking. Same for Yandex, search for "dwell time" (visit duration) in its code/factors.
Some pages, that I won't name, but one of them starts with a pin- and ends with -terest consistently get high google results while offering garbage content.