In this case, it accomplishes efficient backups.
If one has a backup scheme where files are stored in a content-adressable store, I can see the efficiency. But I have never heard of such a scheme in the context of backups.
If one has a backup scheme with automatic deduplication over arbitrary byte ranges (such as ZFS's deduplication feature), I can see the efficiency. But I have never seen anyone enable that feature in the context of backups due to its massive RAM usage requirements.
One example of a system which does that is borgbackup. But even a simple "rsync with snapshots" benefits from identical files, since with common rsync options identical files are not transferred again (which means the data is kept shared between the snapshots).