I agree that taking notes via your phone is a much more convenient and faster, but i find that there is a special element to taking notes the old fashioned way.

Unlike electronics notes, you have to carefully choose what you have write, when you put pen to paper and this slight deliberation makes an idea or scrambling more refined.

Also, if my memory serves me right, there have been studies which have showed that taking notes the old fashioned way is much more effectivc in understanding and recalling them.

Ultimately, a mix of a traditional notebook and an app based electronic medium would be the best compromise.