It's a compact package with many cores, lots of cache memory, lots or RAM lanes, and lots of PCI lanes. All within a large but manageably hot crystal.
Space and power in datacenters are at a premium; packing so many pretty decent cores into one CPU allows to run a ton of cloud VMs on a physically compact server.
AMD EPYC, by the way, follows the same dtatcenter-oriented pattern.
To ask the foolish question, why? My guess would be power efficiency. I've only ever seen them in workstations, and in that use-case it was the number of cores that was the main advantage.