The biggest problem with lights is that they are used often in POI. And when lights cross, it creates a performance problem. That is why POI designers will spend time adjusting lights a lot so they aren't crossing very much. At least, if they care about performance.
So what does that mean for something like spotlights? Unless all spotlights in POI are turned off, showing the lights at a long distance can cause performance problems when it crosses the path of other lights. Vehicle lights are off except on player vehicles, which are limited, which make it safer to have the lights be seen at a greater distance since there aren't a lot of player vehicles in most games, especially compared to POI lights.
Now, can that be improved? Probably. They could increase distances a little or they could make player created spotlights use a different block that has a greater distance so it doesn't impact POI spotlights. I'm sure other options also exist.
I wouldn't mind seeing certain lights on my bar from a distance, especially if I do landing lights. At the same time, some of those construction lights can be seen for many kilometers and should be reduced.