The international sanctions (the real teeth) have already been lifted via the UN action. Iran does not give a damn what the US Congress does. That was hurting Iran was the international sanctions and those have been lifted.
It would put a stop to the 150 billion taxpayer dollars that are going to go to Iran.
It would also let the international community know we do not approve of The Dictator. Of course, it’s not going to happen, but I like fantasizing about it.
And of course other nations were happy to lift the sanctions. Now Iran will buy weaponry from them with our money. What a deal!