Here's the question....
God goes bowling one day, and on his first roll he makes a perfect strike....
So did God (a) roll the ball all the way down the lane from behind the line and manage to knock down all ten pins without tweaking the path of the ball? Or did God (b) secretly and invisibly guide the ball to the pins, or perhaps even secretly run down there and knock over those pins by hand?
Bear in mind, the lane is unusually long -- it takes billions of years for the ball to roll down it -- but also that God made the ball and the lane and the throw.... you might easily say, what evidence is there that the ball didn't just roll itself? The evidence is simply this: the laws of physics are too fortuitous!! The Universe is too friendly to the sort of complexity that we living, thinking creatures embody, when it could have been otherwise in so many ways.
This analogy is primarily aimed at theists who believe that a God essentially stood next to the pins and knocked them down, a silly conceit designed to puff up human importance in the Universe.... a friend of atheistic persuasion suggested of this analogy that "God knew the outcome of the game before he played it. When the outcome was unfavorable, he modified his swing to create the desired outcome." I'd like to think that, like any bowler, "he modified his swing" to maximize the probability of the desired outcome, and ceased to exercise any control over the ball once it hit the hardwood.... on the other hand, while the bowler is just aiming to knock down a particular set of ten pins, God is aiming to create a Universe in which intelligent life pops up -- anywhere, and at any time.... So I think God has an easier task of it!!
If there are, as my friend goes on to suggest, other Universes, it would make sense that God created all of them for the same purpose!! Since God would have preceded time (which is a function of the Universe) there is no need for God to have been "made", it only had to exist -- and if such an entity existed at any point, then by its nature it would have "always" existed!!
There is only one rational purpose for which a being properly described as "God" would create anything -- to learn something that it can not learn in any other manner.... and what other knowledge could God attain from creating the Universe than the knowledge of limitation, uncertainty, and failure? Curiosity is a rational trait, and I would presume God to be rational (as any intelligent being with complete or substantially complete information would be).... I am certainly as entitled to this presumption as any physicist is to presume that mathematical models of the Universe can be validly projected -- we live in a Universe that appears to be organized rationally rather than randomly; if this Universe has a creator, this creator must be at least some part rational.... indeed, the more we delve into the Universe, the more certain we become that it is entirely rational, and so would support the presumption of an entirely rational creator.
Hence, Pandeism proposes, a rational God becomes the Universe (or, as even as my friend suggests, a collection of Universes), and nothing exists of God outside this Universe (or these Universes).... however many there may be, they are logically designed with physical characteristics that maximize the possibility that complexity will arise, and that life will arise from that complexity, and that intelligent life will ultimately evolve, capable of experiencing and reflecting on its own limitation, thus providing these knowledge-completing experiences to God!!
As to the human purpose served by this speculation, well, what human purpose is served by knowing how black holes work? We can't make them or harness their energy for anything.... but we strive to know what's out there.... if such a God exists, it is something that's "out there"; and if it's a rational being, as is the pandeistic conception of God, then we should eventually be able to discern either its actual existence, or at least the probability of it!!