Earlier quoted context omitted.
Zero loss of energy to heat in any of the conductors. You're not making the battery more efficient, you're making everything else more efficient.
That's not going to produce a 20x gain in efficiency. The primary problem with electric cars is energy density in the battery itself. Maybe if mag-lev cars are possible, you could get that kind of gain from the reduced friction.
That's no small deal, but in the grand scheme of things that a hot superconductor can give us.. I mean, this can (possibly, with decades of research) give us fusion, quantum computing, etc.