In Helaman 13:19, Yahweh asks the people to lay up treasures unto him, but the curse dissipates the worldly treasures hidden for personal profit.
Second, Samuel announces that the earth will swallow up the treasures. According to verse 21, the Nephites will bury these treasures when fleeing from an enemy. They cannot take these treasures with them because they are too numerous and bulky to carry, Mesoamerica had no pack animals or known wagons, and the preservation of life would have been more important. The ground, by this curse, will swallow them up and not return them. Archaeologically speaking, Mesoamerica’s climate has rotted or deteriorated virtually all objects that are not stone or metal—objects from their ancient world that would be treasures to us. They have literally been swallowed by the earth—by moisture, mildew, and insects.
In terms of the Book of Mormon narrative, the people will bury their treasures and flee (v. 21) during the next great Gadianton confrontation, during which the Nephites in southern lands (Zarahemla and Gideon) evacuate to the north seeking protection (3 Ne. 3:21–23). The curse tells them that their riches will be gone when they return. (See also commentary accompanying Helaman 13:31.)