you can't use foundation's money the same way you do

with your own money. You can't make political donation with Foundation's money. Buffet donated his money to bill gates foundation so he has no control over those money anymore. Zuckerburg's donation is not completely tax deductible. He use his money to run business style charity. These are great philanthropists of all times.

I think the benefit of having your own charitible foundation is not about financial gains but to designate the money to go the areas that you want it to. So in a way, it is about power. It is having the power to decide how to use it in a charitble way than letting the government dictate.