So on previous Apple computers, one could shutdown using the keyboard shortcut
Ctrl + Option + Cmd + Eject/Power. However, the new MacBook Pro w/ Touchbar has neither an eject nor a power key. Does this mean that the shortcut no longer exists for this computer?
Touch ID button shuts down the computer (Apple Support) Another button on touch bar would be redundant.
Unlike with older Mac notebooks, holding down Touch ID on your 2016 MacBook Pro doesn't display a dialog with options to Sleep, Restart, or Shut Down. You can find these options in the Apple menu. If your MacBook Pro is unresponsive, you can hold down Touch ID for six seconds to force a shut down. Note that you'll lose any unsaved work if you do this.
There is no shutdown button on Touch Bar (except hard poweroff), just a sleep button as customizable option, but we can add a QuickAction with Automator with a shutdown Script and assign a button on the Touchbar. I made a nice red "OFF" button. I wrote the detailed workflow and script to make it in https://discussions.apple.com/thread/251390862, taking the programming from https://discussions.apple.com/thread/8263239.