Yeah, I hear you, we work with computers, why would anyone use something so old fashioned as a pen and paper?
Well, ever since I started programming (and a long time before that) I've always had a hard time remembering things. I'd learn a new feature of a programming language but I'd usually have to Google it again afer a couple of weeks.
For a while I kept some notes in Google Keep of cool things I'd learned. My idea was that I could tag things and it would be easy to search for notes on a particular topic. What actually happened was that I'd never end up remembering what I made notes on and just resort to Googling things again.