Compare data with other users
Allow users to share their sleep info anonymously with the rest of the world's Pillow users. This would give a good idea of how your quality compares to the average of others who use the app. Seeing how this data changes based on country or time of year (during holidays for example) might also be interesting so see.
Joel Semeniuk commented
I think this is important as the data doesn't really tell us if we're doing good or not. How do we stack up against others? What is the normal?