User Feedback :: persistence vs backup

I have been reading about persistence vs backup and I am confused about how they work together. Clearly there is redundency between the two. If you have persistent home and persistent opt, then what more do you get from backup and restore with an unaltered filetool file.

Thanks,
IMF

Persistence provides /home and /opt as mountable partitions with all files being left alone and reused from session to session.

Backup provides a way to save a list of specific files and directories into a single compressed archive to be restored to future sessions.

The persistent directories give you an easy way to keep those directories persistent if you use one computer.

Backup and restore allows you to keep your files and directories persistent across multiple computers, and also allows you to backup files from /etc, so it can be useful even if you also use persistent directories.

original here.