Many have promised that when they die the money should be used for charity. Warren Buffet started this trend.
The bad part here is they can waste all the money however they want and nothing can stop them. Example, they buy cars just to blow them up, not one but 1000. They can afford it. Good for the environment? No, but fun for them as they might have found a new sport.
Often the "claims" of donating the money are complete bullshit. They set up their own charities that they or their children control and "donate" The money to it.
It is just another way to evade taxes and perseverance their generational wealth