I think this is a neat experiment, and I’d suggest doing it many times over just to see what different places and images you get.

I also, like you said, like the idea of the images being “prompted by” an AI instead of a person. But I enjoy it more like a fantasy, because there is no really imagined place; like other commenters have said, there’s only your prompting a description of an imagined place, and that description is generated by a system that jumbles millions of descriptions of imagined places in ways that are more than simply a copy of those descriptions, but never a really imagined place. The system does not learn to imagine places from jumbling description of imagined places: those are two different things. You ask how is that different from the way a human really imagines, and I like your question because it gets my mind going, like a Ray Bradbury story. I think it’s an enticing question, though I don’t have enough knowledge to answer it, but somehow I know in my heart that it is in fact very different. I’ve seen how small kids are able to imagine things and it’s not because they’ve learned it from hearing descriptions of imagined things; they just do.