You dont win gold, you win boosters (and foils in leagues too) that you can open and sell the cards to the merchant.
Current prizes for Dailys are 2 boosters per win, 1 booster per loss, max 3 rounds. So if there are 5+ people making it 3 rounds and you win all your games you get 6 boosters, that is around 24 gold if you sell all the cards within, or even more, if you get any foils in the packs. So you can make more than your weekly gold in a single day, if you win both Dailys.
Also see "League Rules" tab on top of Game Hall for info on League prizes.