Divisions of labor is practiced because

Division of labor is essential to economic progress because it allows people to specialize in particular tasks. This specialization makes workers more efficient, which reduces the total cost of producing goods or providing a service. Additionally, by making people become skilled and efficient at a smaller number of tasks, division of labor gives people time to experiment with new and better ways of doing things.

Division of labor is a mandatory economic process because it is allowing people to specialize in certain things, so this makes specialization makes workers more useful and it reduces the total cost of producing good or providing a service.