The Iranians are just prodding, poking and looking for weakness. I would bet these ships carry nothing, but next time they will come carrying weapons or troops. If they can get Israel to react in the same way they did with the other ships that they boarded, it will weaken the resolve of the Jews. Next time, or when it is commonplace for Iranians to transit this body of water, they will begin the supplying of attackers.
Screwed we are.