ChatGPT and Bing Image Creator are a godsend for my GMing. Mostly because they help to offset my worst weaknesses as a GM - my tendency towards creative tunnel vision, and my limited visual imagination. With ChatGPT I can input my idea for a scenario and have it spit out a list of, "have you considered this, this, and this?" that I can use to flesh it out and make it more three-dimensional. With Bing I can ask for a picture of "a dark alley" or "an ancient temple" and get something that I can either show or describe to my players. Likewise, ChatGPT makes research much easier than having to google for stuff. The quality of my GMing is way, way up as a result.
That said, I always start from an idea I already have, and I accept that the result will usually be a bit imperfect and all over the place. When I have started from nothing and asked for an original idea, the result has usually been, er, interesting. And precision is clearly something I can't expect - when I ask Bing for a picture of three mounted knights, it usually gets over-enthusiastic and draws like ten of them instead. But considering that all I need is some stuff to entertain my friends on a Sunday afternoon, it doesn't need to be exact or accurate, just in the right general ballpark.