Let's say you have an effect that has 1 "main" color.
It can be purple, red, blue - every color and its shades.
But this effect consists of multiple other particle systems.
They all have different shades of this color set as a start color.
Now you want to change all of them to some other color! By default you will have to go thorugh each one of them and change them to the corresponding shade of the new color.
Particle System Color Changer solves this issue and allows you to do that with just a single click!
Warning: Changes only the start color