For example, in cities like Chongqing, where national identification cards are not issued.
When setting up the vehicle, bringing along the license plate number can be considered as leaving a "backdoor." In case you need to travel across different provinces, you can use it legally.
However, if you only have a handheld device and not a vehicle-mounted one, the application will be rejected by the Chongqing Science and Technology Commission if you provide the vehicle license plate number.