One of my acquaintances told me that he uses AI to mass-produce college notes of subjects he himself doesn't know to capitalize on people who will buy them.

Unfortunately I've seen a lot of people are buying his notes. I think this is a terrible thing to do. It's not only immoral but you're making people study on potential AI slop which will compound over the years and that will result in a degradation of the humans' knowledge on the topic in my opinion.

Do not trust online college notes, especially if they're paywalled. There's infinite free knowledge online.