Because it may lead to new classes of high temperature ambient pressure superconductors. Maybe even leading to room temperature + pressure superconductors.

Nickel itself isn't interesting. Any new material is interesting. Yet another YbCo-whatever wouldn't tell you as much as an entirely new metal. It would be just as interesting if it was titanium or vanadium or lithium or any other metal that hasn't ever been found in a superconductor before.