I don't think that's an optimal use. In fact, come to think of it, considering this setup needs to concentrate votes otherwise non-voters cause a skip, Blackmailer's power is greater than it seems.
Yeah, that's a reason mayor could be handed out for. But that exact argument could apply to most of the roles that CE could hand out. Either killed by mafia, or killed by town. Few exists that are likely to not be given special attention by either alignment.
A.K.A "That One Idiot"