If the baker parts with a loaf in exchange for a shilling, he does so because it benefits him. The same goes for the customer: if he pays a shilling, it is because he finds it more convenient than mixing the dough and baking the loaf himself.
The baker earns money from his business activity, but at the same time provides the customer with an efficient service. If we broaden the analysis from the individual to the community and include competition, we can conclude that an economic order based on decentralising decisions and on each person pursuing their own legitimate interest increases everyone’s well-being.