They're figureheads really: give the country an image and a sense of identity. Economically, they generate a lot of money via tourism when opening a part of their palace to the general public. In the past, they were the government; the supreme authority and ruler of the people. They made laws and spent money on improving their peoples lives. In my opinion, it's just a coveted dictatorship and and a way of controlling the masses. If you want a clearer idea of what they do, you needn't look further than politicians. Hope this has helped somewhat :)
