Here is a fuller explanation. The reasoning behind this is to allow you to turn them off without cutting off critical functions that use them:
In iOS 11 and later, when you toggle the Wi-Fi or Bluetooth buttons in Control Center, your device will immediately disconnect from Wi-Fi and Bluetooth accessories. Both Wi-Fi and Bluetooth will continue to be available, so you can use these important features:
- AirDrop
- AirPlay
- Apple Pencil
- Apple Watch
- Continuity features, like Handoff and Instant Hotspot
- Instant Hotspot
- Location ServicesWhile Wi-Fi is disabled, auto-join for any nearby Wi-Fi networks will also be disabled.
- 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.

So, by disabling it, you are, in essence, turning it off. Before you start worrying about your battery, why don't you try it. Bluetooth is the same way:
Open Control Center and tap
. The icon will dim and your device will disconnect from any accessory it's connected to, except for Apple Watch, Instant Hotspot, Apple Pencil, and Continuity features, like Handoff.
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.

So, in response to the need to have auxiliary support for Bluetooth, disabling Bluetooth in the Control Center disconnects you from your Bluetooth devcies with the exceptions of the services listed (Apple Watch, Instant Hotspot, Apple Pencil, and Continuity features, like Handoff).
So, you can suspend it, or you can turn it off completely. But if you mean that by "turning off" Wifi in the Control Center, you don't want Wifi to be invoked, then that will be the result until you meet one of the following conditions:
You turn it back on in the Control Center
You connect via Settings>Wifi
You go to a different location
You restart your device
Also, apparently, this "temporary" suspension of these services will automatically be unsuspended at 5:00 am. This is because you disabled it using the new feature. If you want it fully turned off, then turn it off in Settings.
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