Israel is well aware that any Iranian nuclear facilities are far underground and well shielded. Conventional artillery will have no effect on that infrastructure. Israel is simply "poking the bear", trying to force the USA to intervene.
Now, if your friend or child were poking a bear in the woods, what would your reaction be? Do you shoot the bear? Hit it with a stick? Or do you grab your child and give him a little timeout? Or maybe you just let your stupid friend get mauled by the bear.