The world of numbers tend to address "what if" scenarios. A pencil offers the opportunity to erase while preserving a neat presentation. Economically speaking it normally is a much better financial purchase and people have a tendency not to walk off with your pencil. However, ink provides a permanent signature or details that have been agreed upon. No going back to modify the final document(s). Scanning ink works much better than the faint image of pencil. And, of course the pen delivers a status of professionalism to the owner. Come to think of it - never heard the statement in a seminar "The Pencil is mightier that the sword." Time to look for that perfect pen - and now to ponder what size point and what color ink.