I think the target market is "I have a server in a data centre, I need unattended boot, I don't really need a high grade of security I just need to tick a checkbox saying the hard disk is encrypted"
If your organisation is large enough to start losing track of entire servers, and yet small enough you can't adopt effective organisational controls to prevent such losses, even mediocre encryption might give you some peace of mind - and it lets you avoid reporting data breaches, as the lost data was 'encrypted'.
So there we are somewhat breaking 'Secure Boot' process in general.
Also allows you to do that when you retire a server or cluster. I've been in situations where we had to wipe hundreds of multi-TB hard drives. If you've never done it, that takes a good deal of time. You can get appliances that do it, or try to build your own DBAN rig, but it still takes days. Or you can just shred them, but hard drive shredders are not cheap either, and that's rather wasteful and may not be environmentally conscious.
A large organisation will usually have tedious checks and record-keeping for wiping and discarding hardware, probably instituted after they wiped and discarded the wrong hardware.
I'm not sure why you would rely on just the TPM in this case, though. TPM only disk encryption is rather risky, you'd expect a TPM+PIN setup at the very least.
You'd still be at risk because of this flaw, because the root shell would allow sniffing the key from a secure session. Ideally, attempts to brute force the user account should prevent further attempts by rebooting or refusing further interactive input.