Hey it's their money so they have the right to do what they want with it. IMO the best use of 1 billion+ is to develop products and services that are needed, expensive to develop, and in short supply. If someone identifies such a product or service that cannot be developed profitably (e.g. medicine for very poor people; very long-term research projects; non-economic goals etc), then charity is a way to provide it. There are plenty of people who will do something for profit, far less who will do it at a loss for the greater good. Being a billionaire means you have the luxury of not having to serve the interests of the market, whilst retaining the ability to engage in expensive projects requiring heavy financing. That's a niche that smart rich people like Buffett and Gates can fill. They may fail but that doesn't mean it's a bad idea to try.