It's a container with full os: systemd, journald, tailscale, ssh inside. No need to learn new docker world, just install the deb with your software inside

In a cluster mode, you can move container into another machine without downtime, back it up in full etc., also via one command.

In theory when using ZFS or btrfs you can do incremental backup of the snapshot (send the diff only), but I never tried it.