Title seems a little clickbaity. It's on-device scanning, which is off by default, and seems primarily designed to help you get content warnings on incoming content.

The title seems a little misleading, the support page makes it sound more like they scan incoming, potentially unsolicited images for nudity. I guess if you are in the habit of sending people dick pics, then I can see the title being "Apple can scan your photos or videos to detect whether they contain nudity before the recipient opens them"

Very clever. And it looks like the analysis is local only which skills address privacy concerns.