always had a problem of saving everything and barely using like 2% of that

This hits home. It's just easier to accumulate and not make the actual effort to read, and I would say that rather than reading, it's more useful for learning to write, solve a problem, build something.

I feel the exact opposite. I feel that the documents I've collected but only lightly recall form an extension of my mind. I routinely collect electronic copies of technical documentation and white papers which I broadly organize by topic. To me they represent an accessible knowledge base that I can draw upon when I need to.

I suppose my tendency to collect and organize documents is a coping mechanism for my notoriously insufficient memory. I retain far less than my peers, and will often vaguely remember having read something on a topic but have no recollection of the details or where I read it. Even topics that I go deep on and write about extensively in notes or communication will be largely gone from my mind in months to a year. So my document collection forms a kind of artificial replacement for the memory I never had.