The ruling stated that the Constitutional justification for copyright (and other IP) laws was to incentivize creators. AI does not need incentives, and thus AI-generated content cannot qualify for copyright. Under this line of reasoning,
neither can patents (though note that trademarks derive value from the resources and effort spent promoting them, not from their creation, so trademarks are unaffected).
The act of prompting and customizing iteratively especially in systems which allow the user to submit a prompt ...are clearly creative works that USE an AI not uncopyrightable.
If you want to argue that point you absolutely cannot do so on the basis of a case that literally never addressed that issue unless you would like to traverse the muddy ground between actuality and fiction.
The case literally deals with the output of the AI model, not the input. But on that note...under existing law, code can be copyrighted but not its output. Thus, it is logical to reason that prompts to an AI model can also be copyrighted to the extent they are not strictly functional.
But with AI models and content generally, nobody cares about the prompts/inputs. The output is what matters. (For comparison: Deep Impact and Armaggedon were both the results of the same input: disaster movie in which a team of astronaughts has to go to the asteroid to blow it up before it destroys Earth. The "models" were different screenwriters and directors. Compare the outputs: one is a blockbuster classic, and most people don't remember the other movie.)