All of them could use them. It’s just that it’s becoming more and more obvious that not having them is a national death sentence, sooner or later.
Eventually everyone will have them, either because they made or acquired some, or have been conquered and absorbed by those who already have them.
Not really. It becomes a liability for a small country to have them if they are perceived for that reason to be a threat by a bigger power, which takes over the smaller power to eliminate the threat. Etc. etc.
It also becomes a liability for a small country to not have them when wars of conquest & genocide are regaining popularity and respectability. If they aren’t a threat, then they are a target.
What? Are you suggesting a connection between non-proliferation and the post WWII colonial wars?
/s