The trust dynamic is the opposite of what you think - SGX doesn't enable an enclave that protects the machine owner from the code they execute; it enables an enclave that protects executed code from the machine owner.
The largest consumer application of this is DRM - modern UHD Blu-Ray playback on a PC requires a fully SGX-enabled backend; the negotiation to obtain playback keys and the decryption of the on-disc content is done in the SGX enclave.