I think it would be much easier to sync notebooks across devices if there were user accounts and you just login to the app. That way you could access your files from any computer, tablet, phone, etc, just by logging in.

Files would be stored online through good notes, instead of relying on iCloud syncing or google backups, since i am finding that the iCloud syncing is not reliable.

This would be similar to how you can log into your Google Drive account from any device and see access to all your files if you have an internet connection.

There could also be the feature to download your files for offline use when you know you won't have access to reliable internet for some time.