Wi-FI button on the dock - Improvements

the wifi button in the dock used to have a provision to turn off wifi when it is not used. I assume this is useful is saving battery and preventing unnecessary scans for known wifi network. But since the release of iOS 11, the wifi button simply disconnects from the current wifi network and does not switch off wifi. Please being this feature back. I found the earlier button very useful as one usually turns on wifi only when a known network is available.