Why doesn't "Hide/Show Bounding Box" work in Sculpt Mode?

I've tried to use "Hide/Show Bounding Box" in Sculpt Mode for hiding the top of the head in order to get better access to the throat for smoothing the mesh but it didn't work. Is this maybe only possible with "Dynamic Topology"?

  • spikeyxxx replied

    Never used that.

    But why not use ALT+B to access the throat?