Totally off topic, but maybe the machines in the Matrix needed human brains to solve a proof-of-work puzzle that was more efficiently computed with a human neurocortex. Morpheus just used a battery because it would have taken too long to explain blockchains and ICO's to Neo.
I'm not generally one for the concept of "head-canon," but I think this is now my head-canon for The Matrix.
You see, the Matrix itself is the proof-of-work puzzle, formatted for compatibility with the neocortex. The simulation of a circa-1999 metropolis is not just something to keep the humans' brains occupied while they power the machines; its very substance is a cryptographic hashing process in the form of a simulated world, which also explains why everyone has to be in the same Matrix rather than instanced versions. Agent Smith's real job was just to prevent 51% attacks!
That's actually sort of what the original story was. I mean, no blockchains, but the battery thing was introduced because the studio didn't like the idea of humans as CPUs.
