Think about longevity. Whether I'm writing, drawing, making music, or anything else important to my life, will I still be able to view/edit that data in 20 years? Granted, even with offline-friendly software I may need to port it to new platforms and make sure I back up the data, but at least I have a chance. The data I still have from 20 years ago is far more precious to me than I thought it would be back then. Data that can only be accessed through an external party is ephemeral and it will inevitably disappear one day.