Currently grade reports, as well as other moodle functions that list students such as the "participant list" and the quiz reports allow the students to be sorted by either first or last name. In MANY instances, a listing by "ID Number" would be more convenient since final grade reports in many parts of the world are listed in this order and need to be manually transcribed.

I, for example, often give in-class paper quizzes and then need to enter the grades manually info an "offline assignment". It is much easier for me to sort the quiz papers into rough numerical order first than into alphabetical order, particularly since the students' names are written in Japanese!