Quoted from CaptainNeo:

it's not just the green strip. All your GI's are green as well. GI's are general illumination, which means it's what is suppose to supply the light to the playfield, so you can actually play the game by seeing the ball. If they are any color except white. All people have problems playing the game. Some are actually 100% unplayable because there is some monochromatic color put there. Green is super hard to see anything in, as well as blue, red and purple and orange. You might be able to get away with yellow if it's super bright, but then you might as well go with daylight/sunlight white.