When a card is used as a different type of card, game rules that affect either its natural card type or the card type that it is being used as can affect it. Only special abilities that affect its natural card type can affect it. For example, Covenant and Curse cards at face value can be "used as" an artifact or an enhancement. So special abilities can only target them as a Covenant or Curse, but game rules can affect them as Covenants, Curses, Artifacts, or Enhancements.