What kind of logic is this? If you scored 1 goal, you need cleansheet to win the game. If you don't score, you need a cleansheet to draw the game. Both are important if you want to compete for the league.You literally have to score goals to win games. You don't have to keep clean sheets to win games.
Which one do you think is more important? If you had to choose between a defence that never concedes or an attack that always outscores the opposition what would you choose?
A clean sheet without a goal scored is only a draw.
Why are we even having this discussion in the Xhaka thread? Your argument for Xhaka is now to just stop giving importance to defense?