Let's say your data loss occurs on the Sunday, 31th of a month at 23:55 and then gets synched across all your S3 backups (or it could occur at some point before that but you don't notice it). And poof goes your data.
THIS. I'd say at least half of the time I went to retrieve a good revision of a file from backup, it was already too late and the backup was trash as well.
Let's say your data loss occurs on the Sunday, 31th of a month at 23:55 and then gets synched across all your S3 backups (or it could occur at some point before that but you don't notice it). And poof goes your data.