It's a book, in reality, it would be ultra stupid to destroy your greatest weapon before the greatest battle to come in 3000 years if not more.
By that logic then, we should all be using nukes in any military engagement. They're our most powerful weapons. It would be "ultra stupid" not to.
In political game theory, since the cold war, there has been a concept called MAD. Mutually Assured Destruction. the Nuke=CK analogy is good but it doesn't account for the policy of not using nukes. CK leaves fallout ala balefire not radiation. The key difference is that in randland there is only one nuke/CK. From this point of view it may be reasonable to argue that from a strategic point of view, he just screwed the pooch.
There is a dynamic in RJ's books between typical moral choices and being a good leader. the good leader makes the choices no one else can/should. including ignoring the dead or going to war. I believe he destroyed the CK because the nature of the tool violated the nature of the thing he is attempting to save, it may be best to have the DO destroy the world rather then have the temptation of doing so himself or on accident.IF he did/does destory the wheel with the CK what would be the difference between Rand and the DO?