While processing can avoid the need for color temperature meters, I think that true professional applications exist where they still have a use. For example, with architectural photography where hours can be used in setup of a shot, when multiple light sources all have different color temperatures (example, daylight outside visible, tungsten or halogen accent light, fluorescent overhead fixtures) you can put gels on each of the artificial sources to come closer to daylight balance and verify the result with the color temp meter on that light. Or you could gel the windows to make daylight warmer to approximate the tungsten and halogen sources, in balancing the interior with the outside backdrop. But as someone else said, few people actually need them in photography.