I do not know whether Google gives Pinterest preferential treatment. That said, I'd like to know: What are you searching? Results will be different depending on if you're searching "cute bedroom ideas" or "epistemology in pre-Socratic Greece."
Ha good question! I run a company that builds visual search engines and one of the sites I build and develop is a colour search engine for lipsticks. One of the main ways people discover it is through Google searches so I was studying which sites rank highest for queries like "nyx budapest lipstick dupes" etc. So yeah, for sure, queries for stuff that lends itself well to visual curation will be full of Pinterest results unlike stuff about Greek philosophy.
Give it a few days and this page will be the #1 hit for "pre-Socratic bedroom ideas"
"epistemology in pre-Socratic Greece." has a few results from Pinterest.