No, it is not the place where good alignments get lost – never to be seen again! It is a way of thinking about locating machinery feet so that the shafts are in alignment, even when the feet of the moveable machine may be a few thousandths up, down, left, or right of perfect. Shaft alignment is about aligning the shafts, not the feet.
Think of the shafts as two straight lines – one stationary, representing the stationary machine, and one moveable, representing the moveable machine.