Because it’s feedback on how effective their targeting has been when confronted with whatever electronic warfare and misdirection Israel was using to defend themselves.
That sort of information might let the attacker make adjustments to be more accurate next time
The biggest problem is that the magnets will “quench”, which is what happens when a superconducting electromagnet suddenly stops being superconducting.
There’s a lot of energy stored in that magnet, and when it quenches the energy all turns to heat in a very short time. Any remaining helium will flash boil, turning into an explosive expansion of gas, and the thermal shock will seriously damage the machine