This is neither a fake nor a temporary email. It is unique, made specific by the combination of the user's appleid and the target app/website, and permanent in that it will remain the same. The ability of the user to automatically discard/block content sent to the email address doesn't change this, as it's no different other than (probably) more convenient than setting up a bunch of spam filter rules for those "services" that refuse to remove your address.
It says in the article that it's a 'unique, random address', so I don't know where you're getting the 'combination of the user's appleid and the target app/website' from. The purpose of the service is the same as other temporary email services, to anonymize signing up for services by providing a fake email.
