> 2) is clearly bogus - we know that biological brains don't work that way.

But the brain entire is not consciousness (it's probably in the prefrontal cortex). Some parts of the brain, such as heartbeat, object tracking, etc, are obviously not integrated into consciousness.

It's not one big component, but it at least has to integrate all the components of consciousness (again, not all the brain functions), or else we wouldn't have the apparent sensation that "I" am an indivisible whole. By "I", I mean my consciousness, my will and personality, not my body, which is obviously made up of parts, including the brain and its parts.

It might be an illusion, but that doesn't mean that that illusion is not worthy of study, since it is probably the main thing that defines the human experience.