But if you need to spend the money now, you sell the stocks now so they become cash, which means the stock value is identical to the cash value. That's the whole point. There's no difference between "paper value" and cash value. They're the same.

I mean it might take a couple of days for the trade to settle so you can wire it, but that not the point. The value is just as instantaneous and liquid as cash for all practical purposes, for publicly traded companies generally.