Who did not benefit anything in the westward expantion?

Answer 1

The expansion westward, before, during and after the US Civil War, was an expansion of destruction for Native American Tribal Nations. There were major battles with Federal troops and western settlers. All this eventually led to the Indian Nations to be relocated (against their will ) to Government created reservations.

As an aside, this also happened with Canada's westward expansion and in the former territories of Spain, Indian Civilizations were either destroyed or absorbed into the Spanish speaking people who held power in Mexico and South America. Their absorption however still created an Native Indian subset in these societies.