I just got my new PC set up. First new one in 3 years and it's a monster.
I mostly got it for the Core i9 which has 18 cores. The reason for this is, basically, I compile a lot. Most of my programming involves AI coding and that means doing lots of recompiling and running. I highly recommend 18 cores for most people as it's wasted.
The other reason I wanted so many cores is for Nitrous/Cider work which is Stardock's new engine. I want to make sure that Ashes of the Singularity and Star Control and Game X are all scaling up as you add more cores as this is a major part of our ongoing effort here.