The number of goals a team uses to win a league match is very important to them because it helps them maintain a good position when they are tied with any other team in terms of points. In the case of Leverkusen, the single goal that gave them a victory yesterday was more important to them because of their current position; if they can maintain this form until the end of the season, they will win the Bundesliga. At the very least, if they are unable to score more goals, they should be able to secure three points in each of their matches.
Just as Bayern Munich waits for Leverkusen to lose points, so do Leverkusen wait for Bayern Munich to lose points in order to increase their point differential. Both teams are working hard, and I don't see any of them losing points anytime soon, unless they face each other head-to-head. The race for the league title is still wide open, but it is more likely to be decided between these two teams than any other team in the league.