That's because for many people, email is a to-do list. Once you see the inbox as a task list, you will understand the feature. A to-do list sorted by the time

That's because for many people, email is a to-do list. Once you see the inbox as a task list, you will understand the feature. A to-do list sorted by the time the task was put on the list is not optimal. Some people would like to see the tasks that they have to do this week (send pictures to Emily), and not in three months (check-in for the upcoming flight). I was not aware of this feature myself until just now, but I'm going to be a user of it.