The NIF is a facility for conducting experiments. The goal for the field is fusion power, and these experiments may wind up contributing toward it, but it will never be anything more than a stepping stone. The primary purpose of the NIF is validating computer models for simulating nuclear reactions. These models are used both for the design of nuclear weapons and nuclear reactors. They also develop technologies to support their activities, such as new sensors and laser control methods. Compare this program to say a mars rover where we don't expect the rover itself to do anything of great practical utility, but the lessons learned along the way have many potential applications both directly for future missions, and indirectly for spinoff technologies.