I know that I'm playing into a revival of old thread but the information in this post is worth noting.

It might be something to do with how surface roughness affects heat dissipation. Like for some use surface is roughed to increase surface area to dissipate heat. Opposited to some use where surface that is smoothed show to stay cooler for example this YouTube video I watched awhile ago about cast iron cookware getting smoothed and one section polished leaving three different surface texture in one pan. The large temperature difference between surface variation is most memorable to me. How smoother surface stay substantially cooler.

Skip to 6:59 mark
https://youtu.be/rNrBGi63FFo

Also watch 7:55 mark where egg white are cooked on those surface the rough surface egg seem darker but there is too much variable like the delay where he pour egg white onto rough surface first then flip it first. Plus how the first pour would take away heat from second and third pour.

I know many overclockers sand and polish their cpu heat plate to be perfectly flat for better contact with heatsink and gained substantial performance gain. Would this apply to transferring heat to open air? I dont know. I point out how increasing surface area principle conflict with "smooth dissipate better" like how barrel are finned to increase surface area and in fact cool faster.

Perhaps the surface of cryptic BCG migh lt be just more conductive like how copper > steel for example copper base cookware is used so copper spread heat better across the pan like if coating spread heat from the piston chamber area of BCG to carrier tail area so more heat can be disspated across bigger surface.

Perhaps thermal engineer's input would be more enlightening.