If you have disk encryption, your data now requires the police to force you to produce a password, which may or may not be within their powers, depending on the jurisdiction.
It’s strictly better to have full disk encryption and remote unlocking than no disk encryption at all, because it prevents such „system was switched off by accident“ attacks.
They have kits that allow them to unplug the server from the wall without interrupting power supply, specifically so they don't lose the decryption keys.
Maybe I have a server at home, with a locked cabinet and vibration sensors, that houses a server or two and they all use full disk encryption, but I still want to be able to reboot them without having to connect a physical keyboard to them. So no one has physical access, not even me, but I still want to be able to reboot them.
Or countless of other scenarios where it could be useful to be able to remotely unlock FDE.
The argument was that physical access gives up the FDE key.