If the key is a sizable part of the data, then sorting could allow you to shave a few bytes from the key and reduce the overall storage needed. (Going from 50,0

If the key is a sizable part of the data, then sorting could allow you to shave a few bytes from the key and reduce the overall storage needed. (Going from 50,000 drives to 40,000 drives is pretty significant even for someone who can afford 50,000 drives.) But I have no idea if there are real world cases where that is the right way to compress the data.