Everyone may also have to decide what dangers it may bring. There may be many roles for people to play that are hard for us to imagine now. Ten years ago, nobody would have thought of students creating a website for their school, but that is a role that allows young people to have an impact. Nanobots could, in theory, recognize any kind of atoms and then assemble them into any kind of structure. That means that they could make anything for which their programs have a design.
Diamonds are just carbon atoms arranged into a crystal structure, which is a very simple design.
Nanobots could create food by mixing water with the carbon they pull out of the air. We would use nanotechnology to create nearly anything we could design. This could be done to save people from starving to death, or to conquer another country. Even something simple like fire has both costs and benefits. It sometimes burns down houses and kills people, but it also keeps us warm and cooks our food.