Privacy

You make a valid point, but I still don't see why attestation is necessary. In a corporate setting, sure, it's probably important to remotely verify that the OS is still untampered--except, oh wait, you can do that with the FOSS, opt in, privacy respecting, auditor app. If you install it via MDM you can install, set up, and then block the app so the user doesn't do something dumb.

As for my bank and other such companies, from a legal standpoint I'm already liable if my device is compromised. In almost every Terms and Conditions, it will include a clause that they cannot guarantee your device, or any device you use to access their service, is free from malicious software, and thus it is up to you to keep your account secure.