Tesla made sure its Optimus robots were a big part of its extravagant, in-person Cybercab reveal last week. The robots mingled with the crowd, served drinks to and played games with guests, and danced inside a gazebo. Seemingly most surprisingly, they could even talk. But it was mostly just a show.

It’s obvious when you watch the videos from the event, of course. If Optimus really was a fully autonomous machine that could immediately react to verbal and visual cues while talking,…