Quickly Reboot And Lock Your Mac
With the Touch ID button, you can give your Mac a quick reboot without any complications at all. Since Apple got rid of the power button, you can basically use the Touch ID as an alternative.
All you need to do is press and hold the Touch ID button until you see the boot-up screen. Your Mac will do the rest.
Likewise, you can also quickly Lock Your Mac with the Touch ID button. To do this, you just need to press your Mac’s Touch ID button once, and your Mac will go to its Lock Screen.