Why is a firm’s credit rating important?

Credit rating is the methodology used to identify the overall health status of the business, rating to a firm is more important because, how a complete body checkup helps a person to identify his medical and fitness defects , in such a way rating helps to identify the companies current state of fitness  and suggestions/ factors to be improvised to run the firm for the long run.

Credit rating= financial efficiency + operational efficiency + environment factors+ LOB( line of business they are into for no of years)

Banks do have their internal rating , that helps them to identify the financial factors that cause risk or benefits their lending. But rating report gives the in depth picture of the entity.