Previously, I would either not have illustrations or try to fit a stock image to my use case.
Now I can just generate illustrations that fit my use case well, and it takes very little effort.
Mine is just one out of thousands of conceivable use cases for image generation and editing. I appreciate that this capability is now available to everyone.
Realize the people using this to make slop menus and book covers feel the same way, wow this is useful and saves me so much time/money!
But good art and especially animation, beyond basic UI and logos, is a full-time commitment that requires giving up coding while you're working on the visuals (yes many great solo devs did their own art, but I prefer using the extra time on other shit, like making music and getting on with life)
Getting a good meat-based artist to hop on my Awesome Game Idea #458235 is easier if I can show them a running gameplay example, so they can see what the actual game will be like.
Up until recently I was just using free third-party asset packs like Kenney's: https://kenney.nl/assets/1-bit-pack
That works well but carries a risk of "painting yourself into a corner"; the longer you test a game in a particular art style (or music) the more you subconsciously tend to develop the rest of the game around that style! At least for me
AI-generated PLACEHOLDER art lets me iterate on a game closer to how I envision the final product to look like, right from Day 1.
I'd still hire/kidnap an actual artist before publishing.