Think about how certain individuals that are currently prominent politically have abused the ability to declare the value of their own assets, which are mostly real estate holdings and shell companies.

If you have your own yes-man assessor, you can inflate the value of your worst-earning asset, donate it to a charitable trust you control, take a tax deduction for the amount you declared to offset the cash flow from your better holdings, decline to distribute for years, as your management company manages the asset for operating costs and your financial management company reaps administrative fees, then eventually buy the asset back from the trust for pennies per dollar of its previously declared value, and repeat.

There are no doubt plenty of legal loopholes that enable this. The net result is perpetual tax avoidance, very little money actually getting spent for charitable purposes, and a founder that can declare he is the most charitable-giving person the world has never seen.

It is yet another example of rich people moving money between their various pockets in lieu of actually spending it. The maximum benefit from moving a dollar is realized when the person who moved it no longer has any control of it after the move. The best thing you can do with a dollar is spend it; it is literally that dollar's sole purpose for existing. Allowing someone else to temporarily use your dollar is just a cruel joke upon them, because most of what they do with it will then belong to you.