This is where you are wrong. Or rather, this is complete bullshit.
If u check Ero Dungeon, the artstyle is really simple, it's not high art or really good. People like it.
But if u want a proper critic of AI, Ai is a tool, could be good and well used. The same way Renpy is a tool to help people less good with dev stuff to handle that part.
But even if u use Renpy, rpgm or anything like that, u still need to work, AI is just "use prompt, put example, select image u like repeat".
Zero effort needed, but good, a tool that work so well that make zero effort needed!
Sadly when zero effort is needed for the art, u expect that all the effort the dev should have put to creating art, will be put somewhere else.
The dev mostly used ai for art, Darkest dungeon for the gameplay, renpy for some dev work (still need good effort to make a game like this in renpy it's not really what renpy usually do, so i recognise the effort of the dev here).
So if so many part of the game didnt ask for any effort of the dev, why the other part are not super nicely polished and good?
Balance is terrible and the writing is not that great.
The biggest problem is not AI, the tool is "fine" (depend taste honestly the art is really boring for me after so many) but people use the tool and don't do great on the side.