The killer applications would probably be power transmissions (as saulrh mentions) and magnets. It would definitely help make MRI's cheaper and probably smalle

The killer applications would probably be power transmissions (as saulrh mentions) and magnets. It would definitely help make MRI's cheaper and probably smaller, and I think it would probably help a lot with electric motors. Easy long distance power transmission might also help with renewables (think large solar plants in the Sahara or New Mexico with superconducting lines to bring the power without loss to where we want it)