You have been lied to your entire life. A rice cooker can cook more than rice.
Yes, a standard electric rice cooker is designed to bring rice to a boil, sense when it needs to reduce to a simmer, then lower the heat again to keep rice at serving temperature without overcooking it. That may sound like a very smart little machine, but YOU ARE SMARTER. You can trick the thermostat (just press "Cook" again) and manipulate that nonstick cooking surface to do whatever you want!