All modern browsers/OS come with root certificates from the China Internet Network Information Center. AFAIK these certificates are required for computers sitting behind the Great Firewall to function properly.
Personally I don't live in China and I don't go to Chinese sites since I simply don't speak the language. Thus I don't see any benefit of having these certificates installed. The drawbacks are quite clear however, since China is known to have issued fraudulent Google certificates (1, 2). Is there any reason for me to keep CNNIC certificates on my computer? Could I experience problems with legitimate sites if I remove those?