Burning trees gave humans warmth in the cold and later, valuable carbon for making hotter fires to work metals.

Why would a computer need living batteries when it could just build a nuclear reactor and have steady energy for practically forever. Nuclear power also doesn’t need huge swaths of maintained farmland to feed it, and complicated sewer systems to dispose of the waste.

Even if an AI wanted to be green for some reason, it would be way more efficient to just have huge fields of solar panels. Remember, biological beings get their energy second or third hand, and practically all energy in the ecosystem comes from the sun. Plants take energy from the sun, and convert a fraction of that into sugars. An animal eats those plants and converts some of those plant sugars into energy. Another animal might eat the first animal and convert some of those converted sugars into energy. Humans can either eat the plants or the animals for energy.

If something wanted to use humans for energy, they’d be getting solar energy from plants that have been eaten and partially used by a human body. It would be like having a solar panel hooked up to a heater that boils water to turn a turbine that charges a battery that you use to power what you need. It would be way more sensible to just hook up the solar panel to what you wanted to power.