Since we are already facing unprecedented growth that won't be stopped except by famine, world war or some other calamity, it's important we find a way to stretch our limited resources further and develop technologies that will help us expand beyond earth like nuclear fusion.

Price also tells us whether the new energy source would require government support, or require less resources than building and fueling a new fossil plant, or (if extremely cheap) would prompt people to shut down even brand-new fossil plants because the new energy source is cheaper than the cost of fuel.

Price is important to motivate people to develop nuclear fusion technology, and to finally build commercial fusion plants when the time comes.

Nuclear fission is a superior power technology already, but we've largely stopped building new plants because of the exorbitant upstart costs compared to other technologies.