While money isn't always the most important thing in life, the minions do prove in Despicable Me that having a few pennies/crowns/treasure chests in the bank can often be most beneficial in times of trouble. The minions were the true heroes in the saving of Gru's original evil project in stealing the moon: each minion with his secret stash of wealth showed that working together as a team and pooling your resources can make for a great project. Blind adoration for your boss also seems integral here to succeeding in a mission - although we can forgive them for that, because the little vibrant workers are so damn cute.