A tourniquet imposed in case of venous bleeding of a higher wound does not stop the blood, why?

1) In case of venous bleeding, it is customary to apply not a tourniquet, but a pressure bandage, because there is no need for strong constriction, as with arterial bleeding.

2) If the bleeding is severe and the dressing does not work, a tourniquet can be applied. Moreover, this should be done below the wound, because blood does not flow through the veins from the heart, but to it, that is, from the limbs it rises up. If you put a tourniquet above, then the blood will still flow out. A tourniquet should be applied above the wound for arterial bleeding.