I see it as a futures contract on the value of the BTC. Selling a mining ASIC locks in profit for the seller, betting that this will exceed the time-value generated from the rig itself. Buying a rig locks in a loss, betting that it will pay for itself. We can't be certain whether the BTC will be at US$1,000 or US$1 a year from now. You could make a case for either side, that's why the contract exists.