Rudderrudderrat - No, not "routinely" where on earth did you get that from?! The whole idea is that Airbus has provided us with a dynamic speed showing us exactly what you are saying, a margin that they have deemed "appropriate". So I am talking about possible and SAFE options that are available to you as a pilot.
The FCOM states -
"Minimum Selectable Speed (VLS):
The top of the amber strip along the speed scale indicates this speed. It indicates the lowest selectable speed providing an appropriate margin to the stall speed."
"Appropriate margin to the stall speed" - In other words - using the full range of speeds between Vmax and Vls is considered acceptable should you require or wish to do so. With auto thrust active you will not get below this speed anyway, not even when flying in V/S mode (this is another common misconception).