The net is 20 feet below the bridge, so there's quite the adrenaline rush just falling to the net. After getting caught by the net, you're subject to high winds and quite the view, straight down, of the ocean below. Jumping a second time would be mechanically possible, but would not be easy for a human to do. Without the net, it's a quick hop over the side so having the net allows bridge workers critical time to go and respond to any attempts (which is about one every-other-day).

Suicide attempt survivors often say they regret their choice to attempt suicide. Giving them a second chance makes sense in this context.