I was curious so took the code from here and ran it on my Mac, thinking correctly there might be additional entries since then. Searching the output for "China" gives the following results.
en_CN,"English (China mainland)"
yue_Hans_CN,"Cantonese, Simplified (China mainland)"
bo_CN,"Tibetan (China mainland)"
zh_Hans_CN,"Chinese, Simplified (China mainland)"
ug_CN,"Uyghur (China mainland)"
zh_Hant_CN,"Chinese, Traditional (China mainland)"
ii_CN,"Sichuan Yi (China mainland)"
I would assume the same locales have been added to iOS. It could be a some devices are set to non-Hanzi locales from the above list. I know written Chinese predominates in China, but there are still millions, if not tens of millions of speakers of each minority language.