I am no coder, I use Emacs as my 'DTP package. But I can relate something rom graphic design. Why a graphician should be able to draw stuff with pen and paper rather than only work at the computer? Because the connection between thought and hand is faster with pen and paper. Hence, broadband output and feedback loop. Not just faster but enhaced quality: so fast that feedback loop becomes subconscious, direct, flow. Maybe in programming with vi /emacs the same thing occurs.