well you're not wrong but a room tc superconductor would indeed enable us to cut down on transmission costs of power. I'm not sure if this is obvious but the only reason national powergrids are AC and not DC is because you can step down AC current and therefore have much lower heat dissipation through the transmission lines. So at the minimum you'd get cheaper power by eliminating all the resistive losses and stepper circuits . But also superconductors are used in MRI machines where right now they're kept below Tc using liquid nitrogen, which is hard to control (search MRI quenching). So room temp superconductors would make MRIs cheaper, which would be a boon to the developing world.