How do you know where you are if you haven't been paying attention, and you don't know where you are going? The importance of project management is so clear - is that it allows project managers to know exactly where they are with respect to specified outcomes. Metrics have become so vital to the success of a company's goals, that there are various methods of obtaining these important figures. If you do not keep track of where you are, you could go over budget, you could be way late in delivering a project, or worse, you could be completely off course altogether.
When projects are carefully monitored for progress towards specified goals, they are more efficiently executed. Productivity (another very important component of running a company) goes up, the budget goes down, and the client is satisfied with an on-time delivery.