u/Glitchiness

Before I moved here I had only really seen kiosks for ordering food at fast-food chains, and usually I got the impression that the employees usually preferred you order there since there wasn't much point in distracting them from their other work to order at the counter (sometimes when they were slammed they'd explicitly ask me to do this). But twice here I've seen someone at a kiosk and an employee asking them to come up front to order. What's the deal? Do they maybe not get the tips from the kiosk somehow? Or some kind of additional fee?