As I pondered on this while slurping my coffee, it dawned on me that it is not. I knew this at one level, of course, but hadn't applied that knowledge polemically in this context.
The Genesis account differs markedly from pagan creation stories (and I include modern neo-darwinian evolution in that lot) in three important ways (there are more than three, but this will do for now).
1. It puts mind/person before everything. Most myths somehow presume a 'given' reality that the creation myth is set within. The Genesis account shows the cosmos to be meaningful as resulting from the intelligently applied will of a knowing, pre-existing being: the creator. It is distinct from the creator.
2. It describes a succession of logically ordered events not only in the terms of the sensible (that is, comprehendible) cosmos, but in a historical continuity with our 'life-world' The creation doesn't go through a series of fantasy transmogrifications from one type of thing to another type of thing. People will carp at 'light before the sun'. They need to be reminded that light is but part of the entire electro-magnetic spectrum, the energy infrastructure of the physical cosmos. It had to be first!
3. It sets us in a real reality. The creation is a real thing and is really and reliably perceived. The creation account sets out a rational causality between will (word) and result (the components of the cosmos in our-world terms) that is such as we use within that creation.