Great photo!
Used at Sydney when there's not much downwind on either arrival or departure runways, and the ceiling is above 3000'. Arriving aircraft have to join final at least 8NM out; departing aircraft turn away from the inbound (
mostly!). The runway centrelines at YSSY are separated by a bit over 1000m. Pilots of both aircraft get given traffic information by ATC but don't have to report sighting.
Its purpose here is to direct aircraft noise to the least populated side of the airport. As only one runway is used for arrival, it halves the arrival rate to 24/hr and can't be used in peak periods. The departure runway is much shorter than the arrival runway so some aircraft need to use the arrival runway for departure.