The use of twin locators serves both purposes. Having a FAF reduces the minimum obstacle clearance by 50 ft in the final approach area, but the additional tracking guidance reduces the size of the final approach obstacle clearance area - the areas are trapezoids that get larger the farther you are away from the facility providing (angular) track guidance.
The 737 that crashed in Yugoslavia hit high ground that was right on the edge of the the obstacle clearance area associated with the 1st locator beacon. It would appear that the aircraft used ONLY that beacon for tracking guidance and consequently never got to the MAPt, and was on a continuous divergent path from the FAT and MA track.