> All of the other so-called advantages you can already get simply by running a VM.

Only when you trust the hardware, and hypervisor. There's a huge potential set of advantages here for cloud platforms where people running various VMs do not trust the other tenants, and might not want to have to fully trust the hosting provider.

The possibility of having everything encrypted in memory and encrypted on disk, and with other code running on the same CPU unable to peek at what you're computing might not be foolproof (e.g. you'd have to trust that the provider does not run a CPU that's somehow backdoored), but it would still be a substantial improvement compared to what we have now. It means that a large class of security flaws in the hypervisors would still be unable to expose client VMs, for example.

I do agree with you that un-bypassable DRM is probably part of the motivation, but there are plenty of other uses.