see, thats the whole point...what if you couldnt score higher on the gmat due to a variety of reasons, but you have the personality of a CEO?? you're good at making conversation, have yr goals in life cut out well and the overall objective of yr MBA matches well with the school and the school can really help you with yr objectives....
on the other hand, you have a 790 gmat but dont really know what you want to do in life. or yr goals are such that the school may not be able to help you much with that. you have a shy personality and dont really talk much with the interviewer...that can really screw yr chances...
thts what the interview is for...you can write mountains on yr essay, but do you really have the personality and attitude and mindset to go anywhere with it....