Since the author uses the example of airline travel: I almost always use the automated kiosks -- but I want to have human agents available... because every few years I'll do something crazy like wanting to check in for a four-segment itinerary combining parts of three separate tickets on two different airlines. The automated kiosks don't know how to do this, nor should they -- it's not worth the cost of writing code (and UI) for such weird situations -- but the humans simply ask "who the hell booked this trip" and go ahead and handle it.

The trick is to have humans available for the weird situations while not wasting their time on routine matters; the approach some banks use, of "ATMs are free, but there's a fee for any teller-assisted transactions which you could have done at an ATM" seems to work pretty well.