Insufficient demands in the countries could lead to the inefficient production with unutilized resources, thus causing the point below the production possibility frontier. The countries should engage trading with other nations by specializing in the production and export the potential surplus outputs. By doing so, the countries could lead to the full utilization of resources and both countries result in consuming more on higher indifferent curves than without trade. Furthermore, the international trade would lead to job gains in the industries which the countries specialize in.
Therefore, the countries would be better off with trade.