USA has blown up some much of Iran's launchers, factories, weapons caches, etc. that targets are hard to find.
USA has been dealing with a tactical issue: They have no idea where Iran will strike next.
Lately, Iran has just lashed-out at numerous targets with no goal other than random destruction and intimidation.
They pop out of hiding for a few minutes, fire off some missiles or drones, then go back to hiding. And Iran is so physically big, it is difficult to monitor the entire country.
By controlling the Strait of Hormuz, Iran will have to attack the US Navy in the Strait if they want to contend it.
Now USA will know, generally, where the attacks will have to come from. It will make it much easier to locate and blow up the remaining military assets of Iran.