My understanding is that those motors he uses are pretty special. And I would expect “efficient” to be part of that special. You’re optimizing for torque and accuracy per unit of mass and energy in this sort of space. I know he talked about them in earlier videos but I no longer recall the details.

Aside from the onboard computing required to power the AI model controlling the robot, which also consumes energy, it is important to be as efficient as possible. However, if an Optimus is intended to replace human labour, such as lifting objects and wander around with it, the energy efficiency of the platform becomes negligible.

The platform in the video and the robot dogs from Boston Dynamics are ideal for tasks where they are only limited by their own weight and the amount of computing power required to navigate, such as exploration.

I suppose that's why we mostly see autonomous delivery robots on wheels.

Or maybe I am being too pessimistic about other platforms...