What are the advantages of SM3 and SM4 compared to NIST-approved algorithms (SHA3 and AES) Armv8.4-A will add extended support for more cryptographic primitives, to include SM3, which is a cryptographic hash function used in the Chinese National Standard; and SM4, a 128-bit block cipher; along with SHA2-512 and SHA3. 1 

I am just curious as to why Armv8.4-A added support for SM3 and SM4? It's odd, especially since SHA3 is slightly more secure than SM3 (in collision attacks, but SM3 is more secure in distinguishing attacks). 2 The SM3 cryptographic hash function and AES offer better security than SM4. 3

Question:
Is there any advantage in using SM3 or SM4 over NIST-approved algorithms?
If you are seeking a government contract with China, you might be required to use Chinese government standards for cryptography, just like if you are seeking a government contract with the United States, you might be required to use United States government standards for cryptography.  There are many national pride cryptography standards that have little technical reason to recommend over widely used systems like BLAKE2, Ed25519, etc.  Some of them become prominent enough to matter commercially.