This is because the Chinese government is concerned about the eSIM that carried in the device. eSIM is the reason why mobile access is blocked.
"The advantage of the device that carries the eSIM is, with the software, the user can choose the telecom operator and the communication package itself, but in China, the new system raises questions about how operators and regulators can track the identity of users of the device," the report said. Wall Street Journal.
Blocking by the Chinese government is quite interesting. The reason, local telecom operators, namely China Unicom had previously offered cellular services for Apple Watch at the end of last September.
Hearing of this blocking, the Apple confirmed. "We got information from China Unicom that the new mobile features on Apple Watch Series 3 have been discontinued," Apple wrote.
It remains unclear when this issue will be resolved. However, with mobile access being revoked, consumers in China may choose the option for the WiFI-only model.