So his argument is that the text clearly maps to concepts in the latent space, but when composing them the results are unexpected, so it isn't language? Why isn't this better described as 'the rules of composition are unknown'?
Though I'll also point out that even evidence for that weaker claim is tenuous. It definitely knows how to move an image closer to "3D render" in concept-space, but it doesn't seem to understand the linguistic composition of your request. For example, you'd have an extremely hard time getting it to generate an image of a person using 3D rendering software, or a "person in any style that isn't 3D render"; it would probably just make 3D renders of persons.
I haven't played around with it myself, I'm going off the experiences of others. For example:
https://astralcodexten.substack.com/p/a-guide-to-asking-robo...