Missiles travel. You shoot them in one place and they land in another. For the simple-minded, this can be a difficult concept to grasp. It takes an attention span, the mental framework called “object permanence”, and dare I say a conscience. Those who succumb to the seduction of things being out of mind if they are out of sight won’t grasp the concept of missiles because they can’t believe in the existence of what they can’t see right in front of them.
The application is broad—safety, danger, diplomacy, mutual assured destruction, distance, aim. Just be aware that missiles fly.