The most fundamental argument for panpsychism is that it obeys Occam's razor FAR better than the "emergent animate matter" hypothesis. Panpsychism requires that the universe updates its state by conscious choice, which we already know happens, so from the perspective of Occam's razor we would actually need to explain why it DIDN'T happen for non-animal matter.
Additionally, if we go with the emergence hypothesis, we have to explain the mechanism by which permutations of the states of matter can create a new dimension of "feeling" and "awareness" where one did not already exist. That's a tall order.
Additionally, if we go with the emergence hypothesis, we have to explain the mechanism by which permutations of the states of matter can create a new dimension of "feeling" and "awareness" where one did not already exist. That's a tall order.