The shows main star is the clothes, and so presentation is everything, and this includes lighting them to perfection. If they are lit incorrectly, this can change the look of the designs, which can be disastrous for the designer if it changes the look of a show.
Lighting creates atmosphere. Along with sound, lighting can set the mood for a show and so if either of these are out of sync, the entire show is going to appear off kilter.
Great lighting should be able to add extra flair to the show. The lighting at the highest levels need to be adaptable to these changes so the show looks the same throughout the whole run.

Fashion