*@altieresdelsent* It is true that Clearcoat ignores the regular normal map of the shader and uses an individual one, thus add in a smooth finish on surfaces that are made bumpy via normal map. However, this shader does not use a simple normal map, but displacement. So the detail that you see is in the actual geometry at render time, which means that the clearcoat layer will also follow that bumpy surface.

If you want a completely smooth finish, you have to eliminate the displacement effect and instead use a normal map.

*@Huân Lê-Vương* Good find! Looking at it now, it is redundant. The way this happened is by step by step adjusting the setup. That node served a purpose at some point.

Small things like this usually don't impact the performance that much. What is much more relevant is keeping down the number and complexity of textures like noises. But it is definitely nice to keep the node setup clear of mathematical redundancies!