Sure, but the justification for nations having them is much the same as with private individuals having guns in the USA, and just like the problem the USA has with gun crime, I don't see any path from here to the good world that's likely to get past the political hurdle.
If I read that right, that's not binding on any nation that actually has them, so it's about as effective as non-gun-owning Americans agreeing amongst themselves to continue to not own guns and to say "guns are bad" at those who do, a strategy which thus far has not resulted in the repeal of whichever amendment it is.
