It's invaluable as designers to have quick access to a good notebook, a place to compile thoughts, sketches, ideas, inspirations or even rants. Sure you could use your phone to write things down or dictate with your favorite AI regurgitating and reinterpreting your voice into characters on your retina display, sometimes that is the best solution for the situation. Though there is something completely satisfying about still writing things down, actually putting pen to paper and transferring the images and ideas in your brain through your hands and onto the page. It simply cannot be replicated by a digital device, no matter what Cupertino claims to have created.
Don't ignore this precious resource. Don't stop writing.