Maybe military? There were always $10-20k laptops in near-nonsensical architectures like POWER5, UltraSPARC, dual socket Pentium 4, and such. Maybe they run military radar tools and/or "gas/oil" workloads. Maybe it makes sense for somebody.
That said, who knows, I almost wouldn't be surprised; there's been loads of weird unique systems. Compaq SystemPro had custom SMP support to allow for dual 386s, which IIRC is even supported by Windows NT 3.1 officially. I think IBM x445s had some custom crazy interconnect for 32-way Xeon MPs, etc.
This was in 2001, maybe I am misremembering and it was P3?
That's a lot of jumpers https://www.asrock.com/mb/Intel/P4%20Combo/
Also the two memory slots just somewhere in-between the PCI slots.
Some PCIe 1.0 (maybe also 2.0) boards did similar stuff to allow choosing between PCIe x16 and x8+x8.