Why are the liberated countries striving to create interstate organizations? Give examples.

Thanks to intergovernmental organizations, it is possible to look more attractive in the international economy. For example, the liberated countries of Africa had a rather weak economic base and on their own could hardly compete with the stronger representatives of the market. However, organizations like the West African Economic and Monetary Union allow you to promote your products to foreign markets and sell them within the framework of their own association. It would be extremely difficult to do it in another way.