You should use it as a guide, and also know which schools are typically concider elite and ultra elite. Typically schools are refered to as the M7 or Top16 because there tends to be a drop after those segments.
After you know where the schools are ranked, you then should understand what the schools strenghts are. Because most people going into B-school know at least somewhat where they want to end up, that would change your school choices. IE if you were planning to go to Finance, you may choose a school like NYU or Columbia over say Kellogg since NYU/CBS are really strongly connected with finance. Same goes for healthcare, if you wanted healthcare, Wharton/Kellogg/Duke might be ranked higher.
Generally people would concider schools to be known for 2 major feeders for employment. Harvard/Stanford/Wharton typically are strong in all fields but after that it would be.
Columbia=Finance/Consulting
Kellogg=Marketing/Consulting
Ross=Consulting/GM
Booth=Finance/Consulting
Haas=Entreprenuial/Tech
MIT=Finance/Consulting/Tech
NYU=Finance
Duke=Consulting/healthcare
This is just a slice, in every school there are gonna be people who can make it into every field but it's good to know what each school has strong pipelines and recruiting.