Saving five percent (US) to thirty percent (generic less-developed country) of generated power in T&D losses.

There isn't any obviously-orders-of-magnitude-better application for room-temp-and-pressure superconductors apart from MRI scanners, and those aren't things that the average person would use every day, or even every week, even if they came in cereal boxes.

A ceramic would make a crappy wire. Being flexible is a useful feature for long distances. What you save in transmission loss ends up on maintenance of an expensive brittle material.