Keeping economic personalism in mind, what does the economy do for people?
Since economic personalism investigates the morality of economic actions, I assume that you are asking what the economy does in terms of people's morals; does it make them more or less moral? I will also assume that you are asking about a free market economy.
If so, you could argue that a free market economy allows people to make moral choices. In other kinds of economies, people's choices are limited by the government or by tradition. This makes it impossible for people to truly be moral actors because they are not making their own decisions. A free market economy allows people to choose. They can choose for right or wrong, but they do get to choose.
You could also argue that a marke economy allows people to develop their talents. There is a parable in the Bible that talks about how God wants people to develop their talents, not to simply keep them hidden away. If you take that idea seriously, a market economy is good. The competition inherent in a market economy forces people to improve themselves and develop their talents.
These are arguments that could be used to show that the economy is a positive moral force. Other arguments are, of course, possible.