With Btrfs or ZFS the whole concept of incremental backup is reshuffled: basically you have consistent full backups, only occupying the space of a full backup +

With Btrfs or ZFS the whole concept of incremental backup is reshuffled: basically you have consistent full backups, only occupying the space of a full backup + all the diffs, and you only transfer the changed blocks. It's really something with no comparison to other methods. While I love ZFS, let's not forget that btrfs has its strengths (a lot more flexibility, mainline support), and, provided that your use case is single disk, Raid 1 or raid 10, has been working super reliably for some years now.