Intel Xeon-class CPUs are typically designed for server environments, where TDP must be manageable and therefore sport lower clocks, better voltage binning, access to features on-die that are generally disabled for desktop CPUs, and premium customer support from Intel. Xeons are not something you generally intend to buy only one of, but rather in batches at a time to be used in virtual environments, data centers, and the like.
That being said, HEDT is a strange hybrid area that your average consumer might not even consider; but if you’re a graphic artist, game developer, video producer, architect, or you run a virtual environment in your house or business for various reasons, then it makes sense to have a HEDT class CPU and maybe a Titan Xp or two (or Vega if that graphic architecture actually pans out) to complete large amounts of computational work in as short of time as possible. The upside to an HEDT class system is that you can still use it for everything else, including as a top of the line gaming PC that utterly tramples your average gaming PC. It’s quite literally a jack of all trades, for much less money than the cost of server grade components, and will generally perform better than a higher priced Xeon/Quadro/Tesla type setup.