Hardware-based attestation of the running software is an important security feature, especially in a world where data leaks and identity theft are rampant. Let's say I'm a healthcare provider, and I'm about to send sensitive medical data to a third party vendor. Wouldn't you prefer that this data only be able to be decrypted by a computer that can prove to the world it booted a clean OS image with all the latest security patches installed?
If the vendor wants to install some self-built OS that they trust on their computer and not update it for 5 years, that's their business, but I may not want to trust their computer to have access to my personal data.
Remote attestation gives more control to the owners of data to dictate how that data is processed on third-party machines (or even their own machines that may have been compromised). This is useful for more than just DRM.
If vendors were plain about it, "attestation" wouldn't be a big deal: you do not own the devices, we do, and you lease it from us, maybe for a one time fee.
But companies know it won't actually fly if your plain about it, ESPECIALLY with large corporations and governments who will outright refuse to buy your services or equipment for many key things if they are not the ultimate controllers of the machines for multiple reasons.