The significance of de Vaca describing the customs is to show how the natives he stayed with to lived their lives.
The descriptions of nakednes, and eating of strange food can be seen as both symbolic and literal as seen in the following text “ Three months out of every year they eat nothing but oysters and drink very bad water”( de Vaca 46). It is my belief that de Vaca was saying literally had to eat strange foods, and he wa symbolically