While I agree in principle, it's prudent to remember that "worth" in the context of these ego stroking assessments (stroking the egos of the assessed quote obviously and of common punters who feel smug in the knowing of it, less obviously) is often mostly made up of equity (shares, ownership stake in businesses).

Why and how is that relevant? Because it's not that's why. It's kind of measure of, how much cash someone could drum up if they sold all that equity off. With the one unspoken caveat that because they have so much, any such sale would have a huge impact on the market, and likely see the value of that same equity plummet.

How it is useful is, that it's high time the US (and others) implemented wealth taxes not just income taxes (possibly in lieu of income tax). That is you pay tax not based on your revenue, but based on your "net worth". That is, you have sell off 10% of that equity to the tax man per annum ;-). Old church tithe leveles ;-). Tee hee.

The argument against that is always made by the wealthy and always shallow.