Can any one tell me, why futures contract has no value?

We know that the value of future(Maybe I confuse the concept of future value and future price): $$\textrm{Fut}(t,T) = \widetilde{E}[S(T)|\mathcal{F}_t]$$ How can it be zero? We only have the discounted value of cash flow is zero.

Furthermore, I saw the discussion below, but it seems not useful for my problem. Why are futures valueless?

Can any one tell me, why futures contract has no value?

We know that the value of future(Maybe I confuse the concept of future value and future price): $$\textrm{Fut}(t,T) = \widetilde{E}[S(T)|\mathcal{F}_t]$$ How can it be zero? We only have the discounted value of cash flow is zero.

And why in the forward contract, $F$ is not zero in the $\Pi = V(S,t) - \delta S - \delta_1 Z.$ But just set $V = 0$ to obtain the forward price, it is unreasonable.