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?
The reason is often that writing forces you to already process and abstract the information. Especially if you are taking notes real-time like in a lecture. You will naturally want to shorten the info to write less so you have to process and understand what is the important info, you have to take the info in context of previous knowledge etc. Typing is often much more mechanical, you just need to process the info as it is coming in and transform it into mechanical keypress.
I also remember something about handwriting processing being a nuanced and very separate process from typing, although I am not certain on this. There was also some stuff about reading your handwritten notes triggering memories better than typed notes.