This is a win for both Qatar and the US. DOH benefits from being at a level playing field with DXB and AUH for passenger convenience. The US benefits from reduced border lines and costs on its home soil and facilities and staff paid for to screen passengers that it would normally have to pay for out of its own pocket. It also alleviates the problem of illegal aliens coming to the country and having to detain them and sort out the logistics of returning them to their home country. This way if someone is deemed inadmissible they can return home that day rather than find out once they have reached the USA