In the scenario of headless, if I’m not missing something this only prevents drives from walking off. If the whole machine walks off you are in just as much trouble as not being encrypted at all if you don’t really trust your OS permissions systems?
For example I know that the police in my country use off the shelf disk cloning devices and then some basic forensics software for analyzing the disk image. This can be done by an average computer technician, and such a TPM scheme would totally prevent them from extracting data. Of course for bigger cases they can invest some more effort, but they would have to be sure that there is some important data there to justify the cost.
Try it on a secure boot and tpm2 enabled Bitlocker encrypted drive, the only way to get in is via the recovery key after a configurable number of attempts.
The separate authentication server can be configured to only hand out the storage encryption key on expected reboots, so if the machine unexpectedly walks off and then powers back on that server would refuse to hand out the key, thus the stolen machine is now useless.