Aside from the various recognition+analytical+creative tasks that are only tractable on the human brain ... biology doesn't have much going for it.
It uses carbon, yes, but only in the structurally-weaker forms; e.g. no nanotubes (ergo flimsy skin+muscle, brittle bones, flimsy cell structure in general) and no diamond (ergo weak fingernails and teeth). And it makes no use whatsoever of carbon's heavier quadruple-bonding cousin, silicon.
Oh, and without a nonbiological computer, a human brain has no coprocessor to turn-to for tasks which are intractable for the human brain. (e.g. nontrivial arithmetic computation)
Energy efficiency? That hasn't been a concern at all ever since the Western world got good enough at food production^W^W calorie production to turn obesity into an epidemic (from a status symbol).
Cells aren't flimsy, they're flexible and efficient. Diamonds and nanotubes are going to require quite a bit more energy to produce, and good luck getting them to self-organize and self-replicate. As for use of silicon, it's hugely abundant, if there was a really compelling reason to use it, it is likely biology would have adapted to do so.
Our current obesity issue just highlights the efficiency of biology. Yet, between topsoil depletion and dependence on fossil fuel inputs, our current food production systems are unsustainable. That efficiency might return to importance in the not-too-distant future.
You are right that our machines are very good at simple repetitive tasks, and for that I am thankful.
Evolution has produced hindrances just as easily as it produced our uniquely human mental abilities: the same mental feature that helped us avoid behavioral loops, now mentally impedes humans who perform repetitive tasks. Yet if that task is intractable for a computer, there is no recourse.
Also, for some tasks efficiency may not be enough. Factory machinery can produce and convey products which are far too heavy for humans to lift or push. On the other end of the scale, human vision cannot perceive the hundred-atoms-scale structures in modern ICs; and our fine motor skills are no better at manipulating tools to produce such a tiny structure. (Even producing such tools is beyond the reach of a human craftsperson.)
And that's not even starting on how thoroughly flawed and attention-dependent the human memory system is. Storing less information is all well and good, until important information goes unstored.
And then there's the numerous flaws in how humans perform that array of mental tasks only tractible for humans; cf. Thinking Fast and Slow, which has been discussed on HN recently iirc. I can't imagine how much e.g. mismanagement would not occur if managers were not so ... human.
It uses carbon, yes, but only in the structurally-weaker forms; e.g. no nanotubes (ergo flimsy skin+muscle, brittle bones, flimsy cell structure in general) and no diamond (ergo weak fingernails and teeth). And it makes no use whatsoever of carbon's heavier quadruple-bonding cousin, silicon.
Oh, and without a nonbiological computer, a human brain has no coprocessor to turn-to for tasks which are intractable for the human brain. (e.g. nontrivial arithmetic computation)
Energy efficiency? That hasn't been a concern at all ever since the Western world got good enough at food production^W^W calorie production to turn obesity into an epidemic (from a status symbol).