It is hard to know what horrors nuclear weapons have prevented and what horrors they may cause in the future. So far I would say they have been a net positive,

It is hard to know what horrors nuclear weapons have prevented and what horrors they may cause in the future. So far I would say they have been a net positive, but tail risks are a bitch. But certainly it would be much better to just have a few dozen nuclear weapons per country to stop WWII like events than the thousands that the US and Russia still have that might cause a serious nuclear winter event killing most of the people on Earth. From your link Sakharov had similar musings: “Have Soviet and American atomic scientists helped to keep the peace? After more than forty years, we have had no third world war, and the balance of nuclear terror... may have helped to prevent one. But I am not at all sure of this; back then, in those long-gone years, the question didn’t even arise. What most troubles me now is the instability of the balance, the extreme peril of the current situation, the appalling waste of the arms race... Each of us has a responsibility to think about this in global terms, with tolerance, trust, and candor, free from ideological dogmatism, parochial interests, or national egotism.”