Haven't hooked it up to a badge reader yet. Main use currently is as a garage door alert, have some custom code hooked up to a sensor that alerts on gotify. Just don't want to leave the door open :P Other uses are minor, but like some chat notifications (rocket chat stuff), or major alerts for some of my homelab.
Always looking for more uses!
Uses: Home automation through code red, someone swipes their card at the reader at the door of a building, pages.