When Apple released iOS 11 with a redesigned Control Center in September, they also quietly made a change to how the shortcut buttons for Wi-Fi and Bluetooth worked.
On iOS 10 and earlier, tapping them turned these wireless connections completely on and off. But on iOS 11, it merely disconnected your devices temporarily, while still allowing features like AirPlay and AirDrop to work.
Apple hasn’t changed how the buttons work back to the old way, but at least it’s more clear what’s happening on iOS 11.2.
On iOS 11.2, when you go to turn off Wi-Fi or Bluetooth in Control Center, it now says that it’s “disconnecting nearby Wi-Fi until tomorrow”. The same goes for Bluetooth.
Wireless connections are disabled for 24 hours before they’re automatically re-activated.