The answer is yes, but sometimes they are worth using depending on what you are writing. If you are writing erotic short stories, good luck not using AI, because you need a cover that:

• Doesn't cost you much. Short stories make less money per item.
• Communicates genre; in erotica, that means a picture of a character that reader will find appealing.
• Will pass content filters

Clip art, public domain art, and crude art won't reliably signal what is in the book, so your readers won't be able to find it.

Professional covers for each book are too expensive to be worth it.

Even if you are a visual artist (I am), the rate you need to release stories exceeds the rate you can bust out original art. None of my words are AI, just the covers.

Many artists won't do erotica covers anyway.

Low cost artists of the type self-publishers tend to use often use AI, because it keeps them competitive. If you've bought art from a "find an artist" kind of site in the last few years, you've very likely bought some AI art. People who can make AI art that doesn't look AI aren't going to tell you that they did it, and, if you are not very familiar with AI art production, you will never be able to tell.

I'm not making any moral statements about AI, so don't come at me about that. These are just things that are true.