While the foreshore is natural, the terrestrial edge is definitely not. This shoreline is almost entirely walled off. The walls reduce erosion, but probably their greatest benefit to the residences above is that they allow the terraces and patios to be extended right to the bluff edge, something the ragged natural edge would make difficult. Many of the walls had glass railings bolted to their top edge. The walls also discourage invasive brambles and human trespassers.
Seawalls are often very mundane, utilitarian structures -- unpainted concrete, rock, or timber surfaces that are rarely seen by the people who live above them. But seawalls, particularly high walls like these, are great surfaces for artistic expression, and while this does nothing to address the environmental impacts, it sure makes the walls more interesting to folks on the beach.