Disclaimer: I don't have the intelligence or education to sensibly discuss this topic, but I will write as if I did.
Everything that humans experience and all of human behavior originates from physical processes in the brain; therefore, everything that humans experience, and all decisions and judgements, and all the behavior resulting from the same, is decided, inevitably, by the laws of physics.
Then what purpose does consciousness serve? If all of human experience and behavior is governed inevitably by physical law, then the consciousness of experience and behavior cannot have any additional effect on consequential decisions, judgements and behaviors. After all, it's not as if consciousness operates on some level detached from the brain and above physical law.
It seems that consciousness is unnecessary, that all of human behavior could occur without it, that all of human history would be the same without it. So what purpose does consciousness serve? What evolutionary advantage does it provide a species?