This dialogue is more about exploring the two perspectives than about arguing for particular truths.
Most Creation myths extend the intuition that creation is work done to preexisting materials or from chaos. Creation out of nothing isn’t biblical but was a second century theological move to support God’s omnipotence. In any case, the design argument would be based on an analogy, not an identity of situations. The intelligence of the designers would suffice for the intuitive comparison, even if the superiority of God would allow him to create in a more miraculous way.
The point about the universe being greater than we could intuit has to do with the fact that our intuitions are tied to what we perceive. We directly experience small quantities, not astronomically huge ones. Therefore, the scale of the universe isn’t easily captured by commonsense. That scale is discovered by science, and science doesn’t rest on intuition but on exapted reason; indeed, scientific discoveries are often famously counterintuitive.
The point about disgracing ourselves with theism is that science has won the day. That’s what modernity is about. Theism can no longer be taken for granted, because the Renaissance, the Scientific Revolution, the Industrial Revolution, and the Enlightenment took away most of Christianity’s authority to dictate what the public in developed societies should think or do. Sure, if theism were still in charge of those societies, so that they’d be theocracies, theism wouldn’t be a disgrace. But you’d have to get into a time machine to make that happen.