In fairness this is almost impossible to guess: the is no label and no indication you can press the thing. It was only muscle memory and the fact that my mac now goes into flicker-mode weekly that lead me to discover this.
No hardware power button, then. Which is a problem if the software locks up, as my 2014 MBP does occasionally.
The Touch ID button is a hardware power button. It clicks down like any other old MBP power button.