This is a upgraded sensor vs ordinary light sensor. only limited models exists nowadays such as galaxy s4 series, xperia recent mobiles, and moto x etc.
on first glance, i also thought why this sensor and whats the uses. but after couple of days, i developed this application especially for
1) frequent smartphone buyers:- basically they like to see all sensors in new phone and how its working cool.
2) You can test your RGB sensors whether it works well or have any problem in sensing particular colors.
3) for other kind of electronic project persons whom test their color levels using this app in galaxy s4, etc
4) may be useful to demonstrate childrens for what are colors in particular color light. (use some transparent color papers in a torch light).
5) even more, you can gave 3 torch lights to your children with each color wrapper in each light. they can use three torches and play with your smart phone. i hope this would be fun for your childrens while using physical objects along with phone. (in more three childrens play together and mix a good new color)
6) changing smart phone wall paper based on room light color.
still thinking on other usages...
7) film makers check the light lx value always. so this app may usefull to check light values for each color.
and more ....
Warning: dont show your sensor over direct sunlight or near heavy light sources. i saw the light senser heating little bit when detecting more than 25000 lx approx.
You can also check my thermometer app in following thread