I don’t know who needs to hear this, but billionaires’ wealth isn’t estimated in actual money, but in potential money. It’s actually worse, as people will give them the benefit of the doubt as if their fortune was real.
Of course there are ways for them to convert their potential money into actual currency, but it is rarely a 1:1 exchange, so billionaires’ power partly comes from the illusion of potential money on top of their actual spending.