Take literature for example. We need textbooks to teach us how to live - but literature gives us reasons to live and reminds us that we're humans - not machines. The arts do the same - they express ideas, feelings, perspectives, etc. that words alone may not be as effective in doing so. When society advocates for the arts, we're reminded of our humanity. Of course, we have to be practical too - we can live without a painting - but not without food. My take is that our government should support the arts - by giving tax breaks to companies, foundations, and individuals who contribute to them. Unfortunately the government is in so much debt, that it has to concentrate its funds, at this time, on more utilitarian concerns - like stimulating job creation.
The arts can measure the complexity of a society, the more intricate, innovative, creative arts show us how intellectual the society that generated those ideas are. If a country is so busy with menial tasks for survival the art they create is very simple because they do not have time or energy to invest in complex thought.