It powers the blinky lights
Does what it should. However if you have an RPi running Octoprint, you can do what this does with 5V LEDs or a 12V power supply with a couple or resistors and a NPN transistor. But for the price and convince, it’s nice to have. Just enable in your custom firmware, plug in, and you get the blinky nerd joy we all seem to be attracted to. Less mess.