The Weapon, in and of Itself
Weapons, in my opinion, are a very important part of the martial arts. When you practice with a weapon, you learn to use it as if it were a part of you. It is an extension of yourself. But that takes a very high degree of martial arts training which is why I believe it is important for every martial art to have weapons practice.
Another thing I have always thought of are two different kinds of weapons.
There are weapons where you must first practice with your bare hands for a long time until you are able to use those abilities through through the weapon. Examples of this would be the weapons used in kobujutsu (nunchuks, bo, sai, tonfa, etc) and many (if not all) Chinese martial arts weapons.
There there are weapons like the katana where you pick it or a practice weapon up and start learning how to use it from day one. You don't need any bare handed training prior to learning the weapon.
As you see these are two ways to learn the weapon, but both have and take you to the same goal, to become one with the weapon.
Tae kwon do is not just a martial art, it is a way of life.