Realistic form means the spirit CAN do things the way the form it has taken does things, whether that's eat, make toast, or chill your wine coolers. It doesn't mean they HAVE to do those things, or indeed that they lose their other abilities while in that 'realistic form'; it just means that if they want to do X the way their form Y does it, they can.
Which means yeah, your refrigerator might suddenly start floating around the damn squat.