Color saturation is also much better on a glossy screen; matte screens will dilute colors and look less vibrant. So there is a real benefit to it, but detractors like to ignore that and pretend its just because its "shiny".

My X1 is matte, and therefore its colors aren't as vibrant as a MBP (more washed out, its easy to tell), but there are advantages to matte, like lessened glare. So it is literally a "wash."