With visual approaches:
Controllers can use visual separation. The controller isn't responsible for providing a given amount of separation. The only limit to how close the planes can get is the requirement that the first aircraft be off the runway when the second aircraft crosses the threshold (if not, the local controller in the tower has to send it around).
Controllers can run simultaneous visual approaches to multiple runways which would normally be prohibited due to their relative location/orientation.
Controllers don't have to worry about ensuring IFR separation for missed approaches.