Note that for maximum performance, it's recommended to have /var/lib/lxd on a btrfs filesystem or setup ZFS or LVM and configure LXD to use a ZFS pool or LVM VG. Source
Why is that? I.e. How will those file systems (on the host) equate to better container performance?
Is it computational performance, is it just reduced hard drive consumption because of copy-on-write, both, neither, or something else?
Thanks to @Sven for pointing out that "LVM VG" refers to Logical Volume Manager Volume Group.