Weight = energy. Also, the system is vulnerable since the environment has to be earth-like = pressure, temperature, sunlight, artificial gravity, micrometorites, radiation, etc. etc. etc.
And it is not just glucose that might be produced but all nutrients and elements like oxygen to sustain a human.
Important point: human scientists can create a solution better than nature. Nature is inefficient. Example: a bird vs a fighter jet. Both can fly.
Do you know how the little winglets got on the ends of commercial jets?
Pretty hard to improve on a billion years of adaptation.
BTW, my dad worked in ground support of those fighter jets. it takes a large ground crew, a massive supply chain, a good machine shop and a repair facility to keep them in the air for a fraction of the time.
Birds, not so much.
I haven't seen a sillier intelligent post in a long time. Nature creates flying machines that reproduce themselves for millennia, with minimal input, and those inputs are extremely plentiful. Humans can produce a flying machine, but it requires vast networks of resources and constant input, and the inputs are often scarce. That is not even close to being more efficient.
I'm sure that NASA here is hoping to find something simple, that doesn't require massive airtight housing, and can survive extremes in weather, and still reliably converts CO2 to glucose. THAT would be world-changing (for Mars), and would be worth far, far more than $1m.