For various reasons, you may not want the "main" domaint to be deleted from an account. This could be because it is paired up to billing or in one of our customers use-cases, they give a sub-domain hostname free as a value add to a non-hosting service.
They offer paid-for upgrade where the user can add their own domain.
In the Enhance case, they can delete the main domain and replace with their own.
There needs to be more controls over what permissions the user has at package level.