I believe it was simply for dress/parade display. I know that at the end of the belt (On the front side) a dress dagger or sword could be hung. I'm not sure of the German term for it, though.
Originally, its purpose was to support a sidearm, and even before that a sword, so it had a distinct military connotation. As was mentioned, it was often worn more for show than function. It was used by the SA before the Nazis came to power as it had a slightly intimidating appearance, even without a holster to support, which was useful in their role.
I suppose that is what I am speaking of but in the photo above
the strapping looks white and the strap/belt I am speaking of
is leather.
In Benders books Waffen-SS volume 5 page 168 is an example
of what I am speaking off and also I have seen various photos
of H-J wearing this also....page 105 Volume 3 of the Bender Waffen
SS.
In English it's called a Sam Browne, and it's used to support a sidearm, like a pistol or a sword, so that the waistbelt isn't pulled down on one side.
All armies can be divided into two parts:
1. Infantry;
2. Support arms.