If Iran acquire the bomb they'll use it. They deny Israel the right to exist and have vowed countless times to destroy them. They can't achieve this with conventional weapons or warfare so nukes it is, sure, they'll call it self defence but the fact is Israel could have wiped them off the face of the earth at any time in the last few decades but choose not to, Iran won't show the same restraint when they have nukes.
Israel is free to, and does conduct an "invisible war" against Iran (and other countries). It can do so with impunity because it has nuclear weapons and its opponent does not.
It permanently holds that weapon as a threat to Iran, (and other countries). Israel is very much aware that if Iran had nuclear weapons it would be held to account internationally for its illegal and terrorist activities.
Israel operates an apartheid system against Palestinians.
Israel oppresses Palestinians. It steals their land, Israel steals or destroys their homes and their farms, and starves them of basic necessities. Israel kills Palestinians with impunity and refuses to cooperate with UN enquiries.
It is allowed to perpetuate such conditions because it has nuclear weapons and Iran (and other opponents) does not.
If countries opposed to Israel's racist ideology against Palestinians also had nuclear weapons, Israel would be forced to end its oppression of Palestinians.
Until then, Israel is free to continue its oppression.
Israel would be utterly stupid to use a nuclear weapon, as would any other nuclear armed country. But as has been said many times in this forum, nuclear weapons are a deterrent, not only against a nuclear attack, but also against any kind of power-based action.
Israel is free to, and does exploit that power gained from being a nuclear armed country.
If opponents to Israel's treatment of Palestinians had nuclear weapons, Israel would be forced to moderate its treatment of Palestinians, and reverse some of its illegal policies.
