Obviously just performative signalling that doesn't really do much. You can't definitively tell if AI was used, so the rule can never realistically be enforced. Then again, the Oscars are surely almost entirely vibes based anyway. So it's hardly some internally consistent system of merit in the first place.
A one shot prompt can only get an estimation of what you asked for, no matter how descriptive you are. To get what you actually intended, what you imagined, the process looks quite a lot more like smarter versions of.the traditional workflows for digital effects. (Remove a background, add this thing, paint out that thing, etc.)