Bit iffy on AI assets being sold individually. AI assets in a game is a bit different. I have used some heavily modified AI cover art a few years ago in the earlier days of it before there was a pushback. I inadvertently used a public domain 30 seconds sound sample (Once again I edited it heavily) I think that may have been AI aswell. I found this out later on.
I'm on the fence. I avoid it for the most part. I like to make everything from scratch.