Whether it's worth doing also depends on how much energy it would take to make thousands of miles of superconducting cable of similar capacity and how long such a cable would last.

Not as much as is wasted in generation and transforming, both of which would benefit from superconductors.

The benefit might lie less in the wires and more in the equipment.

Tough to say with a trans Atlantic cable though. Those kinds of distances have never been tried to my knowledge.