The biggest difference between 1SE and iCloud backups is that we're not relying on third party service providers to handle your data and keep it safe.
This is something that we've been working on for a long time now since it will allow us to give better support to our users.
When you back up your data to iCloud, or any other service, there isn't much we can do to help you verify that your data has been stored correctly or to get it back. On the other side, when you back up to our servers we can verify, debug, and assess during the whole process.
If you like playing it extra safe, you can have your 1SE account backups and still create iCloud backups as usual.