Earlier quoted context omitted.
I don't think the actual proposed superconductivity mechanism is the relevant part of this paper. It is much easier to prove that this is superconducting than to prove why. And in a sense it is a bit less relevant. Although developing a working theory for room temperature is also probably worth a Nobel prize, so I am willing to bet some theorists are also running to their blackboards as we speak.
Yeah. BCS was proposed a half century after the first conventional superconductor was discovered, and even today we don't have a convincing mechanism for "regular" high-Tc superconductors. But if it superconducts, it superconducts, and research into the how is useful but not a blocker to using it.
This only can carry a small amount of current. I'm not sure how to figure out what small means (numbers are given in the article if you know how to use them!), but if the losses using regular wire are less than the energy needed to make this stuff then it isn't useful.
This is made out of lead. Even if it is useful for transmission, the difficulty of working safely with lead in a factory may mean it is impractical. Or it make leach lead into the real world making it not safe to deploy.
There are probably other ways this can turn into a "it works but isn't practical" thing that would force us to wait for theory (or luck!) to point to something better. What I wrote above is what I can think of in a couple minutes. Only time will tell though, I hope it works out.