The task of riding a horse can be almost entirely offsourced to the professional horse riders. If they take your carriage from point A to point B, sure, you care about just getting somewhere.
Taking the article's task of essay writing: someone presumably is supposed to read them. It's not a carriage task from point A to point B anymore. If the LLM-assisted writers begin to not even understand their own work (quoting from abstract "LLM users also struggled to accurately quote their own work.") how do they know they are not putting out nonsense?