> Fires, particularly house fires would become less common as wires simply stop conducting when they are overloaded.

I don't know enough about how this material behaves, but a superconductor "quench"* can be pretty catastrophic. I could see a room temperature superconductor battery causing fires from a quench.

*: https://en.wikipedia.org/wiki/Superconducting_magnet#Magnet_...