When you toggle root off using this app and have Magisk installed root will be hidden from other apps. Just a simple tap of the toggle to re-enable root access and you can use root like you normally would. No reboot needed.
The real magic of this app is possible because of Magisk. This requires Magisk to be installed http://forum.xda-developers.com/android/software/mod-magisk-v1-universal-systemless-t3432382