Why use `root-blank` instead of creating a new subvolume?

[musjj]

Instead of doing this:

https://github.com/Misterio77/nix-config/blob/1ad004a17088686100ba8322ca50b772717a030c/hosts/common/optional/ephemeral-btrfs.nix#L21-L24

Why not just re-create the root subvolume like this:

echo "Cleaning root subvolume" 
btrfs subvolume delete -R "$MNTPOINT/root" 
echo "Restoring blank subvolume" 
btrfs subvolume create "$MNTPOINT/root"

Is there any reason for keeping a blank snapshot?