I don’t see that as a design failure. I actually really like them. Electronic door controls both inside and out, plus a mechanical backup only inside. It’s not a perfect design, but neither are mechanical door controls. It’s also not unique to Tesla: many other cars have electronic door actuators with software locks
I’m not an automotive engineer, so I don’t have a great understanding of the benefits as perceived by auto manufacturers. Still, here are some benefits as I see it: