Narrow stance Deadlift allows you to get more hamstrings and glutes into the lift. Some conventional dudes set up shoulder width, but many go closer.
These dudes wouldn’t do it if it didn’t work better. More muscle groups used, more weight lifted.
But close stance squats work opposite. They take more glutes, hips and lower back out of the squat and put most of the work into the quads. Less muscle groups used, less weight lifted.