Everyone wants something - whether this is to rape, to torture, to own a fancy sports car, to rule the world, to marry their perfect partner, to live in a big house, to avoid having to do housework, to lie around and watch TV all day, to be the top of their chosen field, or even to just be left alone. Some people may say that they don't want power, but in fact most of them mean that they don't want power over other people. In fact even this is not true. If you simply want to be left alone, then you are really saying that you want the power to keep people out of your space.
Money is a desirable product because it buys power. Not absolute power, but power none-the-less.