A 'hail of scuds' would be temporary and mild in comparison to a 'real' nuclear threat from Iran.
Of course - nobody has any intention of actually dropping nukes on anyone.
It's about power and leverage, and Iran's ability to project their dominance towards destabilizing and overthrowing House of Saud, and maybe disrupting/overthrowing Israel some day as well.
Since House of Saud actually has nukes (they paid for Pakistani program so that 'in a time of need' nukes will magically appear in their arsenal) all of this is bad for everyone.
In the 'balance of power' it actually makes a tiny bit of sense that 'small actor surrounded by 10 enemies', Israel, has 'secret nukes' because from a strategic perspective, it would be suicidal for them to use in anything other than an existential scenario of defence. If they were not building homes in Occupied Territories, I think more people would probably more readily acknowledge their defensive requirements. Also of course the fact that most people alive today don't have living memory of the many times Israel was invaded/fought wars with direct neighbours, many times bigger than it, and the outcomes were never going to be clear.
It would be better for everyone if Iran just gave up it's nuclear ambitions - there is zero chance anyone is going to invade them, they could join the rest of the world and start using their Oil dollars to buy plastic junk from China and software from the US, and physical gear from Germany - just like the rest of us - their people can be much wealthier, and we could all get along.