Why do people use help dogs?

I always here this. If one of my dogs have a hog bayed i dont want another bay dog to go to it cause all it does is cause a busted bay. Are they telling me that when they have 4 to 5 dogs on the ground they all find the same hog at the exact same time? Cause how in the heck if you got dogs running on the ground can you prevent a bay dog from going to another dogs bay. It sounds to me if that is the theory or fact then you better just run one bay dog. Im not saying i no this or anything cause that is not my way of hunting, If my one strike dog dont catch with the help of the second one they are catching. Its no more playing when another dog arrives. Thats why i dont no what its like to have another dog go in and then both bay.