A professional certification adds credibility to your expertise.  It provides assurance of your competence to others your knowledge, skill and ability to perform a specific job in tandem with your work experience.

For the individual, it certainly distinguishes you as it demonstrates that you are determined to enhance your skill set and knowledge, which benefits you and your (prospective) employer.  For companies who are keen to elevate their brand and service quality, it is a major competitive advantage to have their key personnel and teams certified by a universally-trusted body.