When running in a virtual machine, you may never be sure which physical CPU you are running on - hypervisor can pass anything as CPUID.
For best performance, it helps to use the best instruction set supported by a physical CPU - be it AVX512, AVX2, AVX, SSE4.1, AES-NI, or other accelerated instruction sets. Enhanced Platform Awareness features use top-down approach to close this gap, but bottom-up approach is also possible.