Trusted computing can be used for DRM. I'm much more interested in it as a privacy enhancing technology: the fact that you can have strong guarantees about what can be done with data in the enclave is useful for a lot of applications where you have sensitive data.
(Putting aside the fact for the moment that most - if not all - trusted computing platforms have some security vulnerabilities. Obviously this is bad, but doesn't preclude their utility)
Not really. ARM TZ has been repeatedly blown open, in part because it’s not really a separate core or virtualized workload, but a different “mode of operation” that the standard CPU cores switch into temporarily. Basically going back-and-forth between TZ and your OS if I understand correctly. Turns out that’s a side-channel attack nightmare.