It is either an attempt by Trump to extract himself out of the war by making it look like Iran has folded their hand, though I doubt they have judging by the rhetoric they keep putting out. He will then falsely claim a victory and find out in the near future it hasn't gone away, in the meantime he is shifting Marines from Japan that were there to help secure Taiwan and missile systems given to S Korea to protect them from China and their northern neighbors
Or he needs to resupply his war effort with more munitions as he has just about exhausted his frontline stocks, bearing in mind they thought it would be over in a couple of days.
Either way it reeks of smoke and mirrors.