... how do people make money with them?

When I mentioned to my sister that we were creating Clip Art, she said,
"You should be doing NFTs instead," and sent me this article.

And here's a site that explains them (with a video interview at the top).

The first YouTube video (below, left) explains the phenomenon.

The second YouTube video that explains how to make and sell NFTs.

Want more info? Here's a Google Search for further research.