Hypothetically it all sounds absolutely wonderful. In practice, though, almost no one is lining up to work for free - especially skilled artists who can actually produce high-quality sprites and CG. Most of them, shockingly, expect to be paid for their work.
And if the artist’s work is… let’s say, not exactly impressive, then honestly, you’re often better off using AI than releasing a game with visuals that barely scrape a passing grade. Because if the art looks bad, people simply won’t download the game. Very few people actually want to look at clunky, unappealing visuals. Simple as that.
I really don’t get why it bothers you so much that the author used AI, when they literally state it everywhere. There’s even a warning about it right at the start of the game - so it’s not like anyone’s being tricked here.