yeah, but the threat/risk is still there because they exist. at any moment, the leader of any nuclear-armed country could use a nuke (or somehow have their systems hacked/breached leading to the use of them.) also, they have already been used on civilians (and have killed over 300,000 people). at the end of the day, nukes existing makes the world a more unsafe place. regardless of the threat of mutually assured destruction decreasing the risk of them being used.

the fact is, even if the threat of being destroyed by a nuke is low right now (because of mutually-assured destruction), that risk would be 0 is they didn’t exist. at any given moment, a lot of people have nukes aimed at/near them (there's probably one aimed at near me right now)