Standards are put in place to ensure organisations run smoothly to a pre-determined set of criteria, and to ensure the organisation conforms to the criteria, and if not, it is recognised and corrected. In other words “You Say What You Do, Do What You Say, And Prove It”. The Prove It part is done by way of keeping records which are legible and can be audited.
Certification to a standard (e.g. ISO 9001 Quality Standard) does not mean the resulting product is of a particular quality, it means that you have all the systems in place to assure that if the product (which may be a service) is not as expected, this should be determined before the product reaches the customer. Under this standard the word Quality means fitness for purpose. For example, If you were stranded in a desert, what would represent Quality, water or Champagne, probably Champagne, but what would be fit for purpose, most definitely water.
Customers, especially Government Bodies and Blue Chip companies want to be able to rely on the product / service they receive and so like to see an appropriate standard in place to show that their supplier can meet the criteria. In some cases the supplier may be on the other side of the world, in which case having accredited certification in place should enhance the comfort level of the buyer.