It prevented the infiltration of the Communist in South Vietnam.
As a consequence of US advisory, the United States attacked a portion of North Vietnam which was resulted in the infiltration of Vietnam. The United States Air Force destroyed North Vietnam attempting to perform the subsequent things.
First, to prevent the process of infiltration of the Communist in South Vietnam.
Secondly, to raise the confidence of the South Vietnamese soldiers, and ultimately, to necessitate Hanoi to hold its supporter to the insurgents against South Vietnam.