There's no such thing as the "real value" of anything, only what people will pay. And that is pretty obviously not zero.
I won't further comment on BTC since both sides are staunchly rooted in their positions.
Show me your inherent-value-meter, or shut up. Simple, eh?
That's dodging the question. And in a rather clumsy way. The "use value" of things depends heavily on epoch, person, even fashion and weather. So what is exactly "real" in real value?
> the present value of future cash flows
You don't say! Sorry but a) future cash flows is an estimation at best b) the present value of future cash flows depends heavily on the circumstances of the valuator.
On whether you have a debt to a mobster to pay, or an angry girlfriend to placate..