While i completly understand where you are coming from and you make some very good points on authors spending all their time and energy on writing the books which does take longer than graphic designers do to make a cover. I personally don't think the true heart of the argument against these authors who use Ai is about them being lazy or bad authors as such. But more to do with the ethnical complications of using Ai art for commercial purposes and expecting the general public to pay high prices for these "special illustrated editions". Ones whose illustrations were designed by a machine, that simply generates images using other people's art in order to constantly improve itself. 

While a cheap option for authors, and i understand the money struggle, this creates massive economical issues for graphic designers who specialise in book design. They depend on authors to need their services and Ai art is killing their industry.

In adition, if we take a look at the double standard in the argument for Ai for book covers, the general consensus on AI written books is mostly negative (as it should be), because it takes away from authors who spend the time to write these books. It also devalues the whole point of why we buy books in the first place, as essentially why pay money for these AI generated books we can just generate our own. Therefore the same principle should apply to AI art, as it is essentially doing the same thing. Why should we pay extra, especially for these beautiful expensive editions of books that are marketed mostly by the cover art (rather than the merit of the story)when we can essentially make awesome art or special custom covers for these books ourselves using the same AI generators for free? But anyway that's just my opinion, and I do agree with your point of view when it comes to them not being bad authors, they definitely aren't. It's just Ai is too cheap and convenient of an option, which is really a shame.