[Revel]

So in order to be superconductor it has to be cooled to absolute zero. And this is useful how?

[Mikey_1962]

Efficiency is always useful.

[kidd]

So in order to be superconductor it has to be cooled to absolute zero. And this is useful how?

This is a major threshold of understanding. At one time, superconductivity was only known to occur at absolute zero...now it is found at liquid nitrogen temperatures (and liquid nitrogen is cheaper than milk). One would hope that superinsulation could likewise be found at warmer temperatures.