Active transport is important part of homeostasis as well as many important metabolic processes.
Active transport is a lot like rolling boulder up a hill. The natural tendency is for the boulder to roll down the hill, just as the natural tendency of molecules is to equally distribute themselves on either side of a membrane. However, by spending some energy to push the boulder higher and higher, you have the potential to use the boulder to do useful work that would be impossible otherwise. People drink sports drinks when they exercise to replace some the ions that are important for this pump. Without these ions your muscles freeze up and you get a cramp.