I mean. Yeah. Nukes aren't good. They vaporize, irradiate and kill things. That's why they're A. Weapons and B. Of mass destruction. I don't think anyone who can string two sentences together and made an account here is ignorant of what a literal bomb can do.
But while we're being low key pedantic, might I direct your attention to a little, relatively unknown thing called Deterrence Theory? Basically, "You MAD, Putin-bruh?"
A man saying the hell with his country's relations with basically the entire rest of the developed world in the name of expanding his territory seems like someone who is pretty invested in power and authority. I'm no armchair war tactician, but forgive me for believing that in 98% of cases, having your homeland turn into a smoldering crater is counterintuitive to the "YOU'RE GODDAMN RIGHT!" Empire business.
Then again, deterrence theory is a paper tiger, the moment someone decides to push the button, all value of the gambit is lost, and the whole thing effectively loses it's fangs. It's a very hypothetical, binary type deal. It either works all the time, or the whole world burns.
Still, I doubt anyone, even someone as batshit as Putin appears to be, wants the infamy associated with the progenitor of the end of modern civilization in it's current form.