You can actually directly scan in the Files app from the triple dots menu in the upper right corner, this will allow you to directly scan as a PDF file.
You can get it through Books or on the web:
https://support.apple.com/en-gb/guide/iphone/iphf2746307f/18...
Apart from me apparently.
(Admittedly, I have never read the manual for any iPhone I’ve owned; mea culpa)
Good UX provides clues to discovering additional functionality without intruding on the user.
What’s the alternative? That’s a question for a UX team - something Apple can certainly afford.
This does that. It's behind a button that means "click this for a bunch of stuff you can do here"