In Ukraine they are using tracked autonomuous vehicles for the same tasks. Much cheaper.

It is remarkable how rarely alternative movement styles like slug crawling, flying or rolling get used in the animal kingdom to move around compared to 2-8 legs. If a company can figure out how to do legs and manufacture them cheaply I expect there'd a be a lot of money in that; they must have some sort of practical advantage somewhere in warefare.

Although the tracked drones we see starting to appear in war are terrifying and I'd rather not be on the receiving end of them.

Because biological slip rings don't scale, not because it wouldn't be more efficient on an energy standpoint.