"The licenses Wikipedia uses grant free access to our content in the same sense that free software is licensed freely. Wikipedia content can be copied, modified, and redistributed if and only if the copied version is made available on the same terms to others and acknowledgment of the authors of the Wikipedia article used is included (a link back to the article is generally thought to satisfy the attribution requirement; see below for more details). Copied Wikipedia content will therefore remain free under an appropriate license and can continue to be used by anyone subject to certain restrictions, most of which aim to ensure that freedom."

From https://en.wikipedia.org/wiki/Wikipedia:Copyrights

No, not directly, though they have donated to the relevant foundation, but in any case that isn't quite the same thing.

The use of Wikipedia's information in search results is generally useful to the user.

Pinterest's spamming of search results can harm the user experience, making it harder to find content that is hosted elsewhere. Often the content elsewhere is better than that found on Pinterest because it is more likely to be the original source (or at least cite the original).

Does wikipedia pay its users who contribute the content?

Not an answer but a data point: https://techcrunch.com/2019/01/22/google-org-donates-2-milli...

Wikipedia is expressly marking its content as free, and is interested in disseminating it.

I'm not sure that Pinterest's mission is the same.