I also do not understand why Kompany has to play optimally by playing their core players just to face a friendly match when it is too risky because in a friendly match like this injuries cannot be avoided and Bayern Munich has to pay dearly for it, Kompany must rotate at times like this so that their core players do not get tired because they have to face many matches and honing the skills of reserve players is very important because at times they are really needed when their main players cannot play in the match.
Maybe Kompany is trying to make some efforts to improve a more effective strategy even though the risk is high to play core players in a friendly match because it is prone to injury. On the other hand, they have young players who can be utilized but Kompany doesn't do that and I'm sure he has a different view from most coaches who utilize young players in friendly matches. Bayern Munich will face much tougher competition because Leverkusen also performed so impressively that Kompany has to try to find the best option so as not to lose the opportunity to compete for the Bundesliga title this season.