Yeah I am a power engineer so that's what I jumped to. We lose so much energy to thermal loss..... not just transmission lines..... but if generators were wound in superconducting wires that would be crazy.
Now it sounds like superconductors generally have a maximum current density so there are limits to how much you could shove through it. It's not an infinite current situation.
Anyway hope LK99 is the real deal. Could just be more hype, I am sure Mr. Stu will let us know.