Creating a dual sync on a file or files so that multiple people can edit them at once, each person from his own ipad.
Or just being able to sync the goodnotes account to multiple Gmails (personal and University mail, when the university mail deletes itself after graduation i still can access my data if my ipad breaks).
Could be helpful to people who dont have Icloud because they use an android phone, and google drive is their storaging place.