There really is no need to produce said weapons albeit said weapons are made cause warfare now a days is supposed to be ethical.
I recall watching or reading a nuclear weapon a strong one detonated 285 miles above the Earth has a good chance to fry everything with EMP pulse of at least 86% of the continental US almost 90% of the US population would lose their capability to use digital devices. My best guess is this is fine and dandy but nukes are dirty and are as much a danger to your enemy as much as it is to yourself.
My best guess as to why they created these weapons is to keep as many people alive to create chaos and incite riots and protests basically low generational warfare mixed with 4th and 5th generational warfare.
But again it's just another arms race situation as to why our enemies do it. I'm gonna ignore Iran completely as an enemy as creating a situation with them would probably result in maneuvers done by China and Russia against US. I know Iran isn't 100% evil at least the people, the Government on the other hand with pislamic values IS. But again I'm not quite sure what to make of Iran. They do some good things but also seemingly want to plunge the World into WW3 by their pislamic leaders.