They were built in the past as part of nuclear-weapons-oriented industry of the Cold War. Like many things about nuclear, taking away the need to build weapons changes a lot of the economics around them.
This (need for military-grade plutonium) is only part of the benefits of breeder reactors.
They lift most of the dependency towards uranium providers (needing way less of it), and considerably helps tackling the nuclear waste challenge (producing way less of waste, and less hot).
The challenge is technical: obtaining a satisfying industrial (big, predictable, not too expensive...) breeder isn't a solved problem.
They lift most of the dependency towards uranium providers (needing way less of it), and considerably helps tackling the nuclear waste challenge (producing way less of waste, and less hot).
The challenge is technical: obtaining a satisfying industrial (big, predictable, not too expensive...) breeder isn't a solved problem.