I mean, have you ever tried to have a conversation with one of your cells? Maybe they talk back and we've just been listening wrong.
Once you learned that they do talk back, would you try to rid yourself of them? I wouldn't.
And for some folks, there are pseudo-religious elements. There's been a long line of thought (search Extropians) obsessed with a sort of godhead-merger, or becoming godlike, and related immortality dreams. And just from a symbology perspective, there are a lot of religious overtones. The similarities between Vinge's singularity and biblical rapture are hard to miss, for instance. And just listen to some of the "AI" cheerleaders right now...
We are cheap, disposable tools for machines.
If machines figure out how to farm humans, they're set...it's way more practical than mining resources, refining them, producing materials and using the materials to build a mechanism to travel around in.
It's from the original script at least, not the batteries explanation in the final product.
Or is it that your emotions and thoughts are where all the value is, and a machine executing its function is no different to a hammer?