I think these were no value missiles designed to draw out the David's Sling and Arrows before they send in their sophisticated missiles. That is what I would do. Saturate the areas so the enemy expend all their defensive weaponry and then follow up with more accurate missiles and take out the high value targets such as runways, airplane shelters, HQs, intelligence nodes, power plans, nuclear facilities, etc.
But I do agree with you on one thing: Iran will definitely for in a world of hurt on another level. Question is: can Iran withstand it? And will Russia or China step in to save Iran from Israel in order to poke a finger in the eyes of US and/or EU?