It's good at any rate to have a test run of what people will do. Most people are woefully unprepared for any sort of natural disaster, let alone a full on missile strike. There's not enough proper shelter to go around that would be near enough those who would need it in an emergency, and if people attempt to bunker down in their homes they'll soon discover that water is sometimes not something that magically comes out at the turn of a knob.
Too bad it's all designed to have people on the edge and feeling fearful all of the time, running straight into the welcoming arms of politicians who would pander to that fear. If only people questioned why they were afraid, and started taking control of their own lives and the factors that controlled their lives.