1261,
At PF we're not offering a visual approach, we are merely reminding the pilot to let us know if they do wish to make a visual approach, thereby expediting the traffic situation.
It may only save 5 or 6 miles per approach but over a day that adds up and less miles means less fuel burn which results in savings for the company, it also reduces controller workload and results in expedited arrivals - one of the reasons you will find we very rarely need to hold at LANAK no matter how many inbound a/c we are working.