Unfortunately it doesn't make sense to use us as batteries or energy sources, thermodynamically. But they could maybe use our brains as computers (and this was the first idea the writers had, they just decided against it because it would be too complicated for mainstream audiences)
But in this case it would be rather wasteful to also nourish the rest of the body. As a bonus, if all the remaining people are just brains floating in a tank, they can't really escape.
We think with much more than just our brain. For example, there are neurons at the stomach level and your gut bacteria determines part of your mood. You could make a case that the whole body is required to capture the human experience.
In that film (brains in a jar), you don't escape to reality, you escape to a different level of the matrix (one where you've got superpowers). Last shot in the film will have a lot in common with the last shot in Terry Gilliam's Brazil.
> and this was the first idea the writers had, they just decided against it because it would be too complicated for mainstream audiences
Doesn't make immediate sense to me, if using brains as computers you wouldn't want to occupy them with the Matrix simulation and the whole story falls apart, so how was the complicated plot ought to be? Use the brains with the Matrix how we are used already for solving captchas?
> use our brains as computers (and this was the first idea the writers had, they just decided against it because it would be too complicated for mainstream audiences)
