I'm still fairly sure the reason for the wall and bridge is in some way tourism related.
As posted by others, the picture is of the bridge and rock, not something else which is just out of shot.
If there were a lighthouse just to the right, then why is the picture not of a lighthouse, rather than the pathway that leads to it? This assumes that the person taking the picture is 'normal' in the sense they take pictures of 'normal' things - but I say that as the kind of person who may well take a picture of the bridge or rocks (not the lighthouse) because those kind of things sometimes interest me more! The question is whether an Edwardian photographer would use expensive film and photographic paper to take a picture of a mundane feature, rather than the far more impressive lighthouse.
For me the rock (or the view from it) is the attraction, it explains why someone took a picture of it, and why someone went to some effort building a bridge to it. We are talking of something like Giant's Causeway, Smoo cave, Devil's Hole (Jersey), Old Man of Hoy. (not suggesting it is actually any of these)
The only thing which concerns me is that if this was some kind of tourist attraction, then presumably it would still be. But in the internet age, lots of people would have posted pictures of it online... but having done various image searches, nothing similar comes up. Why?