It is generally considered to be smart budgeting to put money aside in good years that you can tap into if a catastrophe (personal level - accident or unemployment, State level - Mt. St. Helens, serious economic downturn) occurs.
If we pay into it in good years, we don't get tapped for it when we can least afford it (or have the state borrow it and pass it on to our children). It's just a fiscally responsible way of handling our money.