Yes, it's a term used to describe someone riding a bike without a helmet.
Yes, it's a term used to describe someone riding a bike without a helmet.
Assuming a flawless lamination on the CPU and cooler, you could run it without thermal paste. My belief is there’s no need for it and it might even hinder performance by adding an extra barrier for heat flow. Removing the paste could improve thermal transfer, potentially enhancing cooling efficiency. Yes, the thermal conductivity would likely approach that of copper since that’s the exposed metal surface.
We're referring to perfect optical flatness. Even with that, temperature changes would likely lead to enough movement for poor contact. In practical applications, using thermal paste is standard because heat transfer between mismatched parts isn't intended. If it did work, thermal conduction might be feasible since nobody has thoroughly examined this before. Assuming it did, the result could be better due to the IHS and cooler effectively forming a unified surface. Thermal conductivity would resemble that of copper.
This, whilst technically correct, rather misses the point; the surface area for heat transfer is only relevant if there's something for it to transfer to. The infinitesimally small decrease in surface area you may get from lapping a CPU will be massively outweighed by the potential for better contact.
Consensus reached – minimizing the substance that generates warmth and the means to release it is ideal.