Not really.

You cannot ask why consciousness exist. That would be like asking why a circle exist. To elaborate if we consider that our reality is computable from a set of physical laws and a set of random events, then it implies that the consciousness inside that reality is also computable.

The next question is whether the subjective experience those consciousness, or those consciousness themselves can exist without something actually doing the computation.

Does a circle exist before someone draw it? It does, right? and thus, if a world with consciousness is definable, then the subjective experiences inside those consciousness will happen without something actually computing it.

So all such possible worlds exist. By "exist" I don't mean the classical meaning of it. Just that there are subjective experiences going on "inside" them.

I think quantum mechanics also converge on the same idea with the multi-world interpretation of quantum events. At every point when there is a random event, the universe is split and all possibilities is realized in disjoint universes.

And I think this is the same thing as I have described above. Actually multi-world interpretation would be the final nail in the coffin for physicalism. How can material world split infinitely at every infinitely small instance ! But evidence shows that something like that is happening.

So it has to be something like what have been described above.