The squat, featureless surface gives drug dealers nowhere to hide their secret caches. The angled sides repel skateboarders and flyposters, litter and rain. The cambered top throws off rough sleepers. In fact, it is specially crafted to make sure that it is not used as anything except a bench. This makes it a strange artifact, defined far more by what it is not than what it is.
The Camden Bench is a concerted effort to create a non-object.