Any other job the head of state ever had are taken away.. they only represent the country, and yeah they cost a lot. But they also bring up some money, maybe more than they cost.. who knows.
To go into this discussion at a higher level.. Today the 'economy' is the main subject of our lives, which I think is totally wrong.. everything orbits around the economy and money making.. while it'd be way better to care for eachother more and just 'be human'.