I don't think the universe cares if anything notices it.
You are not showing how proto-consciousness in itself has a use.
It is not a consciousness. So what is it doing?
I think proto-consciousness is an easy answer that doesn't really answer anything.
If there are no metaphysical laws, then you're right, the universe does not care if anything notices it.
I think it's possible to propose the idea because I don't think the problem of proto-consciousness is as hard as the "hard problem" of consciousness.
Anyway, speaking from pure physics you're right, it needs to have a purpose. But from what I heard from Penrose, he had reasons to draw this conclusions not only to solve the problem of consciousness but for other reasons as well.
If those reasons were coming from physics I haven't found yet because just started to scratch the surface of their theory. I'll try to dig it out, or maybe someone else knows?
But ok. So you say
"A consciousness has a purpose (If free will exists). It helps with survival."
If the many worlds interpretation of quantum mechanics is true, the universe splits for every collapse of the wave function, if I understand correctly.
So everything is happening essentially in different time lines / parallel universes.
If an organism wants to survive, it has to navigate this higher dimensional maze of parallel universes to find itself in the one where it survives.
In other words
If an organism wants to survive, it has to make conscious decisions that leads to its survival.
Do you see the connection there?
Basically,
consciousness is what is navigating the organism towards survival in this sea of different time lines.
consciousness is a complex system of proto consciousness, which in turn are collapses of the wave function.
Where wave functions collapse, the time line splits.
So... where proto consciousness takes place, time line splits.
So coming back to, consciousness is a tool for the organism to use to guide itself to the time line where it survives.
It doesn't answer the question why proto consciousness would be needed in physics,
but I think if the many worlds interpretation is right then consciousness as a tool for survival and proto consciousness as the collapse of the wave function goes quite well hand in hand.