This exactly! I think with pen and notebook. I also think without pen and notebook, such as during my driving and running. Without notebooks, I often find myself think in circles and having hard time to recall what I just realized a short moment ago. With pen and notebook, it is more relaxed. Often I don't revisit my notebooks. So the notebooks are mainly serving as a thinking aids than to serve as a database. Replacing them with digital sounds nice, but in reality it is just a distraction. Having the record to go back to is a short term benefit; the few pages of notes that I do end up revisit often quickly become part of paper or presentations, or tweets and moments, or more often, prototype code. I have accumulated a drawer of used notebooks. They only have sentimental values. And they have more sentimental values in paper forms than in digital forms.
PS: my current favorite notebook is this one https://www.amazon.com/Universal-Sugarcane-Notebook-College-... A hard cover and thick ring has become a necessity for me.