They are part of society and it's worthwhile to them. What they do with their wealth is up to them as indeed it is for you. Who knows what is necessarily good for 'society'? Politicians are constantly telling us what's good for society and they get it wrong most of the time IMHO.
It used to be the case that if you were fabulously wealthy you would put at least some money to help the needy. Bill Gates does a lot of this today. I'd wager that a lot of the wall street fat cats don't do this.
As you say what they do with their money is up to them.
I say that they shouldn't earn as much money, and that they should be more like Bill Gates.
