No one “wins” a nuclear world war 3. That said, there have been in the past and will be in the future criminally insane individuals who are given or who steal ultimate power in their country and are willing to try to “win” such a war anyway. That’s why who has this sort of weapon has always mattered.
Of course it may only be delaying the inevitable.
It all depends on your definition of "win".
If "win" is defined as "I and my ruling elite are alive, and nobody is now in a position to challenge our rule over what is left of the world", then perhaps some individuals DO consider a nuclear exchange "winnable", regardless of how many millions are dead among the peasantry.
Correct. The Brookings and Rand corporation think tanks war gamed the use of tactical nukes. Note, one corporation is liberal and the other conservative. Both think tanks came to the same conclusion, the use of tactical nukes always lead to total thermonuclear war with both sides launching their big nukes.
Tactical nukes are good if your enemy does not have nukes.