Not to mention how much faster searching through a text file is compared to a word doc (eg, you could ctrl+f the headings name and have a result instantly).
Why don’t you just ctrl+f in a word doc/PDF? That’s still possible, but it’s not exactly of much help in many cases. E.g. if the headline you are looking for is the name of a basic concept that appears all over in the document. Page 512 only appears once.
All other forms of indexing are content-dependant. Indexing by page works the same on any page-based document.
Why don’t you just ctrl+f in a word doc/PDF? That’s still possible, but it’s not exactly of much help in many cases. E.g. if the headline you are looking for is the name of a basic concept that appears all over in the document. Page 512 only appears once.
All other forms of indexing are content-dependant. Indexing by page works the same on any page-based document.