I use AI to help me brainstorm for my fiction sometimes. Sometimes for basic things like names, other times to help me reword certain sentences. Possibly the most useful so far has been getting ideas to visualize a sparring scene. Knowing nothing about fighting or different types of holds and such, I described with a lot of specificity how the two characters were positioned. How character A was restraining character B. The idea was for B to instruct A how to get out of the situation.
I first got some ideas for how this could be done by straight up asking for different methods character A could use to get out of B's grip. I then got it to write some ways that B might explain this, or instruct A. It went so far as to have B offer encouragement at strategic parts and such.
The final version ended up being heavily edited of course, but it helped greatly to visualize the scene and the physical actions.
I also used it to help me brainstorm my way out of some plot knots I got myself into. Like "Imagine such-and-such situation. What would be some possible reasons why so-and-so would choose NOT to perform this particular action?"