One of the issues readers have been reporting is that disabling Wi-Fi and Bluetooth from Control Center in iOS 11 doesn’t seem to disable them completely, they are required to disable it from the Settings app to disable them completely which they found quite annoying.

Apple has confirmed that that is the expected behavior in iOS 11. Bluetooth and Wi-Fi are not fully disabled when turned off in Control Center in iOS 11. When you turn off Bluetooth or Wi-Fi in Control Center, the iOS device will immediately disconnect from Wi-Fi networks and Bluetooth accessories, but they will continue to be available for what Apple calls important features such as AirDrop, AirPlay, Apple Pencil, Apple Watch, Continuity features like Handoff and Instant Hotpot and Location Services.

Apple explains how it would work in the new support document:

Disconnect from Wi-Fi networks

While Wi-Fi is disabled, auto-join for any nearby Wi-Fi networks will also be disabled until:

• You turn on Wi-Fi in Control Center.
• You connect to a Wi-Fi network in Settings > Wi-Fi.
• You walk or drive to a new location. 
• It’s 5 AM local time.
• You restart your device.

Disconnect from Bluetooth accessories

If Bluetooth is turned off, you won’t be able to connect your iOS device to your Bluetooth accessories until:

• You turn on Bluetooth in Control Center.
• You connect to a Bluetooth accessory in Settings > Bluetooth.
• It’s 5 AM local time.
• You restart your device.

If you want to completely disable Wi-Fi and Bluetooth for all networks, devices, and features, then you need to turn it off from the Settings app.

This can be a little confusing but I think it makes sense to keep them available for features like Apple Watch and Apple Pencil.

What do you think?