For the Iranian government, the purpose of its arsenal of ballistic missiles was to deter any direct aggression, allowing the country to subvert its adversaries through violent proxies without incurring retaliation. That deterrent has failed. The idea that Iran can be attacked whenever its actions displease its opponents is clearly unacceptable, and so the Iranian government wishes to re-establish deterrence by imposing such a cost on the global economy that further attacks are not contemplated. The mechanism for doing this is the closure of the strait of Hormuz.