There are multiple reasons for relying on the human touch. In one case, Duplex didn't appear to pick up the cues that reservations were available. It may also need training on more real-world calls before it can handle every situation. More importantly, the company argued that it was taking a cautious approach. It wants to treat businesses with respect, and that means gradually transitioning to the AI as it becomes better-suited to dealing with staff.

If there's a main concern, it's that Google may have oversold Duplex's capability. It pitched the technology as capable of handling all kinds of reservations, but that's not always true. There's still a lot of learning left to do, and it could be a while before you can assume that an AI will handle tasks like this.