Oops, I said build instead of pack here as that’s likely what you actually want to use.
build-incus is equivalent of build-dir + pack-incus.
The reason why we do it in two steps in our CI is because we produce both LXC and Incus images so that lets us use the same rootfs for both. But if all you care about is the LXD/Incus image, just use build-incus directly.