I have tried both. Going fully digital and fully notebook oriented. The best I have come up with is to have long term notes in a note app but your on going current thought process in a book. Like what you are currently doing or it's process.

This helps with the search and copy issue of going physical. But writing things for your ongoing process / tasks makes you remember things so much better. Sometimes, all I have to do is write. I don't have refer them. But if I have to, I usually have a better sense of how I got to the end result cos I have the journey written down in my notebook. Also being a fountain pen lover helps.