If you have a 300-page legal document, and other sources reference passages, e.g., a paragraph on page 234. It would be unreliable if over the years or depending on the viewer it moves to another page.
that's why legal documents number the paragraphs, otherwise it's unreliable over the days you edit the document, no need to wait years for the app to change layout
Isn't the solution to that not to fix your document’s pixels, but rather to have auto updating references (a la LaTeX)?