(Against merely “average” human performance, a π0 would beat the entire planet by a factor of six).
It's more like this: http://dwarffortresswiki.org/index.php/User:BaronW#The_Almig... . Not just horrendously inefficient, but also highly at odds with what the brain is designed to do.
Of course, in terms of raw speed, my laptop can learn to read handwritten digits from only the examples in the SciKit-learn python module in 0.225 seconds [1], a bit less than the time it takes a human visual system to go from “some photons have hit the retina” to “there is a thought now, and that thought is ‘three’.” — the architecture of the AI is nowhere near as example-efficient as the architecture of a human brain, and it is only winning by the absurd performance difference of the hardware [2].
[1] https://kitsunesoftware.wordpress.com/2018/03/16/speed-of-ma...
[2] https://kitsunesoftware.wordpress.com/2017/11/26/you-wont-be...
Wiring up some neurons to perform binary arithmetic could be much more efficient. But there was never an evolutionary reason to do so.