There would be many benefits to the United States implementing the sort of national health care system that other countries such as Britain and Canada have had in place for decades. The first benefit is that you would get better health outcomes for less money. The United States currently spends a greater portion of its GDP on health care than other OECD countries and still has shorter life expectancy and higher child mortality.
Another major benefit would be ethical. There is something fundamentally immoral about the richest country in the world letting people suffer or die for lack of medical coverage.