I found Thunderf00t's video on LK-99 to be funny because he pointed out something no one else did: In almost all applications of superconductors, they don't use high-temperature ones for one simple reason: Material properties. Most high-temp superconductors (including LK-99, he was assuming it was one, since he's not qualified to say one way or the other) are a ceramic. The ones that see use in the LHC, for instance, aren't. They're metallic, so you can form them into the shape you need without having to manufacture it in that shape to begin with, since you'd need another superconductor to join pieces like glue, which we don't have. That alone doomed LK-99 to the department of "cool, but not super useful", since most of the really interesting uses were for large things, not small ones.