Pencils vs. Pens

Questions, questions...
So, here's another one for you, which is better pencils or pens? Why? State your opinion and reasons why.

Pencil Pros:

Pencils are erasable which makes very handy for younger children and active writers.

Pen Pros:

Pens are very official. They write smoother and are don't need to be sharpened.

So, which is better? and why don't people say 'The pencil is mightier than the sword.'