With so much note taking apps nowadays, I can't understand why does anyone still write notes with pen and paper. You need to bring the notepad, book or that paper to retrieve that information, and most of the time you don't have it in hand. While my phone almost always reachable and you carry when you go out. For those still like to do handwriting, there's many app does that and they can even convert it to text notes.
So, if you still write notes with pen and paper, why?
For work I used to have an agenda with notes but over time I realized it's impossible to actually keep organized and have the most important things be the most easy to find. I moved to onenote and never looked back.
For personal notes I use a tablet with pen because it's fun to write by hand without wasting trees and it still being digital it's easier to organize and move information around.