The thing about this data is that it isn't controlled for quality (probably, I only skimmed the article). I don't support AI "art" myself but I don't bother checking the AI disclosure normally unless it looks clearly AI generated.

EDIT: I got around to reading the original PC Gamer article it's implied that various factors are controlled for. But realistically there's no way to actually control for the quality. They apparently filtered out obvious slop though. We can conclude from the data that AI disclosure reduces sales, or that AI use reduces game quality, or both.