Having nuclear weapons and using them for deterrence is what has kept the peace throughout history. Believing abolishing all nuclear weapons will bring peace, is simply folly. There will always be some countries who will threaten our way of life. By having nuclear weapons we can keep peace by mutually assured destruction.
Nuclear weapons are far better than the runner up. You can also use nuclear weapons for semi/non lethal attacks. They are also the best thing if you see an asteroid at the last moment, if it is small explode it, if it is large deflect it.
we need for protection
If a country is too stubborn in a decision, you pin them back to obedience with this phenomenon.
Whoever said they have kept peace throughtout history, we have only had them a few decades which doesnt qualify as "throughout history". In the miniscule time weve had them they cause several diplomatic disasters, destroyed two cities, almost accidently went off an unacceptably high number of times, and started a decades long cold was that you can argue isnt even over. Mutually assured destruction is not a way to keep peace. If you have to have that for peace it isnt really peace.
If all countries got rid of their nuclear weapons (hypothetically), then we wouldn't need to worry about deterrence and we wouldn't have to waste money and time maintaining them.