SGX attestation is unnecessarily complex

I’m not sure if this is a constructive issue, but it seems that the attestation process is overly complex. In particular, the PCE attests a QE, which then attests the third-party enclave. It would be much simpler for the PCE to attest the third-party enclave directly. This would also avoid quote verification having to check that the quoting enclave identity is correct.

I imagine it is too late to change this, but I am curious what the reason behind this design decision was. The only documentation I can find is that the public part of the PCK might be considered confidential, but that only applies to legacy EPID-based attestation (which is approaching EOL).