You're right about the backup situation, but I would still say that even just having your personal data in a flat file backed up with OneDrive - which a lot of

You're right about the backup situation, but I would still say that even just having your personal data in a flat file backed up with OneDrive - which a lot of users probably have set up without even fully realizing - still beats the app-specific cloud for most purposes (both access- and privacy-wise). Just consider the difference that it makes in the mental model of vendor lock-in. And yes, it may not be that common for people to lose their Google account, but that's really just one failure mode of relying on in-app storage. The provider may decide to suddenly put parts of your data behind a paywall (like Slack just did), or may straight up cease to exist. Even if Microsoft were to do something similar to your OneDrive account, you'd still have your local copy and could change your cloud backup provider with very reasonable effort.