Exactly. It immediately puts you on equal footing in ANY and ALL negotiations.
Im not saying it should be this way or that I am actively encouraging 3rd world countries to do so (as if one could do such a thing from this forum), but I also have the (very ordinary) capability to remove myself from the equation as an American and see the advantages/disadvantages associated with a country like Iran/Venezula aquiring nuclear weapons.
Madmen or not, natural resources or none, there is much to be gained from being able to tell the developed to off, in no uncertain terms. That, like it or not, dictatorship/socialist or theocracy, my nation is sovereign, my power to rule is absolute and no outside influence will tell me how to govern, period.