Chiming in with a slightly different perspective: I often bookmark things I see in passing that might not be useful now but may in the future based on things I know I want to do.
Case studies in certain engineering/programming tasks, something I read that I found useful and want to have handy to share with others in the future, project ideas or notes for long-running efforts I pursue and sometimes want a "bucket to pull from" for instance.
While it's certainly true that I probably _use_ 10-20% of what I bookmark, I don't think it would be possible to realize the same positive outcomes without the 80% that I don't. (Just last week I was able to braindump a large piles of 'examples/essays I found helpful learning about neural network optimization' to one of my engineers because I'd kept them handy after they helped me.)
I should say though, I sense this is a slightly different use case than the "I want to read this article just to read it" bookmarks where I know I never will, which is certainly something I've experienced but is a minority case in my life nowadays, so I wanted to vouch for productive scenarios too.