In a BO2 game there is a possible of 3 points given out. If you go 2-0 winner gets 3, loser gets 0, if you go 1-1 each team gets 1 point.
The reason the points are distributed that way is so there is incentive to try to win in both games. Teams that win 2-0 get an extra point, whereas the team that is down still gets something if they tie, instead of just 0.
LCK does it the same with their BO3 series, 3 points on the line, if you go 2-0 you get 3 points, if you go 2-1 you get 2 points losing team gets 1. Its in your best interest to try to win the entire series 2-0 to prevent the other team to score any points at all.