Made for hotkey use - if any lights are visible - the script hides the lights - if all lights are hidden - it makes all light visible. Good for quickly hiding and unhiding all your scene lights. Note: While there is a toggle under display to show or hide lights - if you hide a light and then uncheck that box - the light is still not shown because you manually hid it. This script does not have that limitation.
The only major differences between script packages are slight version compatibility issues - there are no new scripts added between the 3 packages.