It's not like it gets you nothing; photosynthesis would be much less efficient in terms of the land footprint required. The article discusses the footprint requ

It's not like it gets you nothing; photosynthesis would be much less efficient in terms of the land footprint required. The article discusses the footprint required for their facilities relative to normal agriculture; the difference is massive. Photosynthesis is effectively driven by a 2D flux and thus is constrained by surface area to a pretty large extent – unless you use an electric light source, which would require renewable energy to be sustainable and thus, again, be constrained by surface area (think wind farms and PVs). With their technology, they can use a bioreactor and aerate it with the CO2, etc. required to grow the microbes they're using. That means the energy is not constrained to a 2D flux and can be delivered across all three dimensions in a volume.