As we can see Girona took advantage of the momentum well. So Girona steps in La Liga are very well calculated. They know that no club can interfere in Real Madrid and Barcelona eternal rivalry in La Liga so what Girona can do is take advantage of the situation. Girona could lose to both clubs but the probability with the other club is actually higher. So this gives Girona a breath of fresh air sacrificing matches against Barcelona and Madrid but on the other hand they are fighting for big opportunities with the remaining clubs. For me, Girona strategy has been quite effective so far, with the result of 13 matches and one loss being a big achievement.
Your point is very valid and I think it's exactly the strategy Girona has been using since this season because, on a second taught, if they win every other team and loose to only either of Barcelona or Real Madrid, they will stil continually climb and maintain the top position on the table, the only time it could really cost them may be toward the end of the season if they point happens to be all they will need to rank up the table.