It is important (to many), especially when there are kids involved. It's not just a piece of paper it is a legally binding committment to each other. If it is important to your mate, and you are serious, then why not? The ceremony is not a waste of money. It's a milestone in your life that you, your wife, kids & family will look back on and smile.
Don't be afraid, it's over so quickly and you will be glad you did.