Nuclear weapons stopped the Cuban missile crisis ending in nuclear holocaust

Such was the thought from a friend.  The problem is, however, that the very nations who have the most nuclear weapons to wipe humanity off the face of the earth the greatest number of times, are the very ones who cause the most wars, viz: USA/UK/Israel, Soviet Union/Russia.  Their possession of WMD is no brake on their extremist tendency for warfare and, in this century and last, for killing the greatest number of people ever seen in the history of humanity.  Nukes are no deterrent to aggression and violence.

The enormous stockpile of WMD was no disincentive for the USA to put Jupiter missiles in Turkey near to the border with USSR, nor was it a discouragement to the USSR in their bid to put missiles (ICBMs) near to the USA landmass.  It was this one-sided, aggressive policy of the West that caused the Cuban missile crisis in the first place.

The truth is, these nukes are so destructive, with the blowback of radiation on the attacker, too that they are just too impractical to be of any use in a crisis or no crisis; in time of war or in time of peace.  Therefore, they are not deterrent.  Why have them when they have to remain unused white elephants, stuck in their underground silos for ever or, having to be moved around the subterranean depths of the world's oceans in a cigar shaped metal tin?

Could these nukes simply bring the thought to these imperious states in the nuclear club that they can throw their weight around in the world?  That they can strut around like self-important, gilded peacocks to use coercion, force, aggression and violence to get their way whenever they want?