Yep, notebook processors don't have Heat spreaders, because it would only hamper the heat transfer, and they are assembled in factory and stays the same through the life of the notebook.Whatever they call it, it doesn't matter. It is (1) an extra thickness of nickel-plated copper between the die and the heatsink, (2) it requires two layers of thermal interface material instead of one. All of these things reduce the transfer of heat per unit of time into heatpipes or a waterblock.
Intel knows this; we know this. Whatever Intel wants to call the IHS, it's there to protect the die first, and "spread" the heat as second priority.
But give average Joe bare die CPU and see what happens while he tries to install his DH-14 D: That's what IHS is for.