I suppose the upside could be that you _could_ imagine (if, of course, the whole thing was efficient enough) a process where you use low-carbon electricity (nuclear or poorly-timed renewables) to power CO2 capture from air, and then turn the CO2 into starch, and then maybe turn the starch into something edible ? (I don't have enough grain of salts to take my own words here...)

It's a huge stretch to image that being competitive with conventional agriculture. Still, just imagining a situation where we could use electricity to turn CO2 into food...