When exporting pages to images (something we do quite a lot in comics), it helps with further batch processing to have a sufficient number of leading zeroes as part of the exported filename.

So instead of:
Page 1
Page 2
Page 99
Page 103

Page 001
Page 002
Page 099
Page 103

This can be a selectable feature in the user preferences or automatically generated to pad the number of leading zeroes to match the number of pages in the exported file (e.g. if there are only 93 pages in the book, only add leading zeroes to 1-9 so all numbers are two digits. If it's 103 pages, add two leading zeroes to 1-9 and one leading zero to 10-99).

This is default behaviour in Acrobat, so already exists within the Adobe codebase.