Just as 1200lbs of torque does a Miata little good, a 296583906283906829034689023869023-core Xeon that costs as much as a used car does a gaming rig little good. Two main words to keep in mind here are "diminishing returns" ... once you go over a certain # of cores you're spending lots of money for marginal/no gains or perhaps even performance loss
pcie connectivity varies between boards, expensive(to buy run and maintain), proprietary board layouts that may or may not fit in a gaming case, most multipliers are locked, and games dont scale well past 4 threads
Most games are run by the graphics card anyway... unless you are so low end that you bottleneck. You don't need to spend a lot on a million cores when the main portion of work is on the graphics card.
Because these CPU's have lower clock speeds. Gaming usually uses around 2-4 cores if you're lucky. Any more and it just can't utilise all the threads. Server CPU's are a bit slower but have a lot more cores.
Because most games uses 4 cores at top, server CPUs are huge and they are different platform, well you can run win server or LINUX(most likely linux) on it, but it won't have the happy graphics card you see on your gaming PC
... I dont know, is it because its for a server and not for gaming? I mean, not like motherboards with the chipset for that cpu would fit your case since, server mobos are more complex and complicated, right?
i have been gaming on dual CPU systems since 1996, and haven't really had any issues. started with dual Pentium Pro 180's, P3 866, p3 1100, and dozen or so dual Xeon system.
all you need to do is pair it with a good gpu