The reason why direct coin mining is disabled for the Haudenosaunee and Lakota, and for the Tribal Marketplace to be introduced, is due to the belief among both that one must respect nature, and mining (among other things) is seen to be offensive towards nature.
The Lakota traded buffalo (bison) hides and meats with other tribes and also with the non-Indigenous settlers of the Great Plains. Buffalo was very important to the Lakota because they used nearly every part of the animal to supply their needs, and it was also one of their main sources of food. They created a preserved cake called pemmican—a mixture of dried buffalo meat, fat and wild berries or fruit. Buffalo bones were used to make their utensils, and the skins were utilized for tipis, clothes, and bedding. Even buffalo bladders were put to a practical use: they served as water containers supported on wooden tripods (look for one in the Lakota Home City).
The Haudenosaunee primarily traded tobacco, pelts and wampum (a traditional shell bead currency of the Northeastern Woodland nations of North America). Like the Lakota, the Haudenosaunee also traded with neighboring tribes; and after the arrival of Europeans, they began to trade fur and tobacco with them, acquiring metal items like knives, axe-heads and cooking pots as well as firearms.