Iran's principle strategy is to impose severe economic consequences on the US and its allies, to tip the balance of resolve in their favour. This is easy for them to do, because closing vital shipping lanes and attacking energy infrastructure in the region is done at only the cost of a few drones -- whilst defending this is incredibly expensive. This asymmetry is the only one which is profoundly in Iran's favour, and their best strategy for forcing a diplomatic resolution. This is why they are attacking multiple US allies in the region.