IGNITE TALK

This wasn't really my big question but now it is : the use of nuclear weapons.
What are nuclear weapons used for in this modern time ? Threats ? End all life on earth ? Show countries that you are superior?
What I learned during spring break is nuclear weapons is very deadly to life and earth. United states spends $179 billion for a nuclear arsenal.
The certain nuclear  bomb we have right now is the B83, it is 75 times powerful than the bombs that were dropped in Japan during World War 2.
This is sort of related to Fahrenheit 451 towards the end of book when Montag sees the city get bombed and demolished
I'm going to look more information about today's war and if countries are able to release nukes.