I recommend it over a full disk backup because I can automate it. I can’t automate full disk backups as I can’t run dd reliably from a system that is itself already running.

It’s mostly just to ensure that I have config files and other stuff I’ve spent years building be available in the case of a total collapse so I don’t have to rebuilt from scratch. In the case of containers, those have snapshots. Anytime I’m working on one, I drop a snapshot first so I can revert if it breaks. That’s essentially a full disk backup but it’s exclusive to containers.

edit: if your goal is to minimize downtime in case of disk failure, you could just use RAID

My method requires that the drives be plugged in at all times, but it’s completely automatic.

I use rsync from a central ‘backups’ container that pulls folders from other containers and machines. These are organized in

/BACKUPS/(machine/container)_hostname/...

The /BACKUPS/ folder is then pushed to an offsite container I have sitting at a friends place across town.

For example, I backup my home folder on my desktop which looks like this on the backup container

/BACKUPS/Machine_Apollo/home/dork/

This setup is not impervious to bitflips a far as I’m aware (it has never happened). If a bit flip happens upstream, it will be pushed to backups and become irrecoverable.