What is the importance of the Island of Misfortune in the novel, The Moor's Account?

The Island of Misfortune is where the expedition ends up after they are abandoned by the governor. The survivors make their own home on the island and spend a great deal of time there. Mustafa starts to learn the native tongue from the Indians. Many of the survivors develop a sickness and pass away. The remaining soldiers choose to desert the group because they don’t want anything to do with the Indians.