For one thing, it's hard to know what to spend it on. What should take priority? Obviously your own basic needs, for starters. And then of course the needs of your immediate dependents. But then what? Do you try to increase your quality of life? Theirs? At what point do you draw the line and begin to help others altruistically? Are two coins worth more than billions in practice? Besides, what even is quality of life? It's a very difficult and heavy problem. One I'm glad I don't have.