One of the things I didn't include in the story, since it was more of a hunch on the part of the robot's makers than anything based on the pilot, is the notion that people might be more likely to make service item requests if they don't have to deal with a human. That could be because they don't want to worry about tipping someone for bringing an item, like a toothbrush, that's ostensibly free, or because they simply don't want to deal with someone after a long trip. Or, and this is where some data would be valuable, there's the anecdotal "evidence" of female hotel guests just not being comfortable with opening the door to a stranger, if it's not absolutely essential. Again, not exactly a concrete benefit, but I think it makes a good deal of sense.