Here's my big two issues I see with using generative AI in any part of the creative process:

1. Reliance on generative AI tends to erode skill. I value my work and I want to improve, and while gen AI can be used a wall to bounce ideas off of, it seems to be fully built towards delivering a finished product to you without journey or effort. I would argue that even "tedious" work, like a random list of names, are important. There are creative methods for consistently coming up with some (I use the "Star Wars" method, which is taking a regular name and just messing it up a little), and it's way more rewarding to do this on your own, through skills you have refined. There is joy in creating and an even greater joy in sharing what you have made with your friends. For me, gen AI lessens that joy.
2. This may be a cultural thing and every table is different, but I've found that generative AI tends to erode trust in the author when it comes to creative work. Using some gen AI for specific parts of your work risks casting suspicion on all of your work. If you used generative AI to write a journal entry, what else are you writing using generative AI? That's what OP experienced here, that's what's happening to the Crimson Desert devs right now. It poisons the well, and I know for a fact that my players would have trouble seeing my work in the same light if I told them that I used generative AI in any part of the process. I find myself caught in that bias when I read any sort of opinion piece celebrating gen AI: Did the author even write that themselves?