You certainly can use it as a batteryless inductor coil to zap people, similar to how you zap people with a charged capacitor. But a superconductor is limited b

You certainly can use it as a batteryless inductor coil to zap people, similar to how you zap people with a charged capacitor. But a superconductor is limited by the magnetic field strength it can support. When the magnetic field strength goes up beyond the critical field by increasing the current, superconductivity is lost. In superconducting magnets, this causes a catastrophic failure called a "magnet quench". So a superconductor cannot store unlimited energy. In the original LK-99 claim, the critical current is 200 mA, it's not much.