The value of Bitcoin is equal to the amount you would loose doing the transaction by other means.
Not quite though. Suppose there is task X that is worth 100 units to you. Without Bitcoin it would cost you 200 units to accomplish, so you don't do it. With Bitcoin it only costs you 60 units so you do it and profit by 40 units, not 100 or 200. Bitcoin makes you 40 units better off and likely makes your partner better off by some amount as well.