"communication in the brain is done with chemical signals that are orders of magnitude slower than electricity and use much more energy" A nitpick: the neurons

"communication in the brain is done with chemical signals that are orders of magnitude slower than electricity and use much more energy" A nitpick: the neurons actually do use electricity to send signals and (looking at the neuronal model in its history¹) it actually evolved to send signals along as fast as it could. The chemical component, AFAIK, is the physical implementation for memory, so this is kind of the storage class regarding operation performance. Overall though, I agree that our cerebral organ may not be the apogee of computational performance. ¹ As far as I remember, the dinosaur neurons didn't had myelin, which for some large animals caused non-trivial sensorial delay.