You could bump into Bazza anywhere any time, just a random chance thing. 

Or you could create a hazard of any description ,and you can be certain he will happen along and bumble  into it.

Fish are no different, slightly less accident prone perhaps, but if you build it they will come.

None of the limited success I've had - at Tauranga, suburban Waitemata, and in Northland - has involved berley. But that's mainly because of the terrain: usually shallow flats/channel edges.

But if I was fishing off a classic Northland or Coromandel rock ledge, and based in one main area - not constantly moving around a long area of coastline - i reckon berley would be a significant advantage in getting baitfish/kahawai to hang around, and therefore targets for passing kingies to investigate.

Put it this way, I can't see where it would be any kind of disadvantage, other than the weight to carry the berley and dispenser/ropes etc in and the need to carry back stinky plastic rubbish etc.

Topwater off the rocks is a game of percentages: based on the frequency of passing kingies, which may only happen once every couple of hours, and putting a lure in front of them in those short windows. So unless kingies are passing by very regularly, increasing the odds in your favour with berley is worth it, I reckon.