Human bodies are terrible electrical power sources…even if you harvested all their metabolic heat or chemical energy, you would get far less usable electricity than a comparable mass of conventional fuel or batteries. Much more efficient ways to turn biochemicals or biomass into energy exist.

And to use us as batteries we need food. I would venture to say at least 99% or more of human food production requires sunlight. So just use sunlight for energy. No sunlight because of horrible nuclear winter or something else blocking the sun? Create satellites to collect it and beam it down with microwave lasers.

Anytime you convert a form of energy to another you lose energy. So sunlight->food->human->electricity is not only inefficient but dumb. An AI would never do this. The Wachowskis were writers, not scientists or engineers, and it shows. What would we be good at? The human brain is exceptionally good at massively parallel, low‑power pattern processing: recognizing, predicting, and adapting in complex, noisy environments. This sounds like the exact sorta thing you’d need if you were creating a virtual world. The trick would be getting the interface right. Assuming they had enough time that could be accomplished. So the whole reason the rumor of us being used as processors instead of batteries, is because it makes WAY more sense.