We don't write to produce objectively "good" writing: we write to communicate. "Good" writing is writing that accurately and successfully communicates to the audience the thing the composer wanted to communicate. It is always contextual in the context of both writer and reader.
The computer has nothing it wants us to understand. It writes for no purpose, which is why it is flooding systems like Clarksworld submissions designed to support purposeful communication. It may eventually be able to evade the detection algorithms that for now have prevented it from completely shutting down human communication, but that won't make it "better": it will make it a successfully DDOS attack on society.
but, unlike many other businesses. humanity needs creativity and art for its development as a society. AI created art is somehow part of that, but its domination prevents the development of art by actual humans.
it is not a question of what is better, but what is actually creative and furthers human development. AI created art is not that.
the point of being human is continuous development. an AI can't do that. it can only summarize existing data and not generate new insights on its own. (doing that can help humans generate new insights, but that is something different)