It makes sense once you have an industry large enough to move substantial amounts of mass to and from Mars. Space elevator saves energy. In the proposed form you need only 0.52 km/s of Delta-v to get from Mars' surface to the elevator. And on the other end of the elevator you can release (or catch when importing) that mass at 3.52 km/s of Delta-v. Of course, there will be some energy loss moving up and down the elevator, but you don't need the acceleration that a rocket launch demands.