The korean guy say this is a 1d superconductor (as opposed to 2d sheet or 3d, which means you would need a single line of superconducting molecules from end to end. Its likely why it doesn't float all the way as only parts of it has these and scattered all over the chunk of solid.

However, if they perfect 1d production, they can layer in a bunch of them to create a quasi 2d or 3d superconductor.