Dirty bomb will still render half a city uninhabitable for generations.
And, there is a decent chance the Russians have been recycling spent bomb cores for their current bombs. Just because a core loses its potency, doesn’t mean you can’t refine it again and mix it with other refined cores for a brand new bomb.
Is true that the tritium for hydrogen bombs would be basically impossible for a non nuclear nation to get, but conventional fission bombs are readily recycliable.
What’s the name of the cow you get your raw milk from?
Do you get a veterinary report about her with every bottle of milk?