sometimes we have an enviorment sphere connected to the reflect node or just in the shader.
now imagine we have like 6 material zones where we need this enviorment map connected.
what if we change this image? should we then change it for 6 or even 10 zones? 

i made an image called AM_panorama for apollo maximus. i connect this in the shaders. now its done.
now everytime i want to change it i just open an image editor and change it there. i save it as AM_panorama and it will be updated in the shader. this is very faster and you dont even need to go in the material room.for a car you can have a Car_panorama_viper.