Apple's mobile phone traffic and wireless network can only be switched on and off in a unified way, and cannot be set separately. What's going on here?

1, turn off the use of WLAN (the button is grayed out)

2. At this time, the mobile phone uses mobile phone traffic.

3. Turn on the WLAN (the button turns green)

4. Mobile phones will give priority to wireless networks. If the wireless network signal is poor, the traffic will continue to be used, but there will be a prompt.

5. Applications using cellular mobile networks: Each application can be set separately.

6. The mobile phone can be upgraded at any time. Various loopholes can be fixed in time.