It is all about tax breaks and what is included in personal property. Many states and individual counties are proactive in offering companies 10 year exemptions from property taxes to induce companies to relocate.
It must be for tax advantages. I found the below that states if a company creates a passive investment company and is domiciled in Delaware, no state income taxes are levied, and they provide tax savings through businesss expenses and dividend deductions.
A PIC is a separate corporation created by a parent or an operating company. PICs are "physically" located in a tax-haven state such as Nevada or Delaware. Nevada has no corporate income tax. Delaware does not impose tax on companies deriving income from intangibles possessed or owned in-state.
Sounds like a loophole (like the sly friend with the same moniker who posts here occasionally).
These must be significant tax breaks for this conservative crew to expend this kind of coin for a headquarters move.