A good question. Why do I need a certification? It is just a nice piece of framed parchment with nice letters hanged on the wall.

It costs a lot of money and nowadays they send it by mail. You must print it and frame it yourself. You must go thru an expensive exam maintain the certification periodically. 

And do not forget, if your employee pays for it, you must explain him what he pays for, unpleasant situation.
A lot of negatives, are there any positives? After all you are an expert in your area, you keep yourself up to date with the last news in quality management or security management or business continuity management. You know everything related to management of incidents, CRM, Big Data Analysis, Root Cause, fire detection and defects prevention, but …. I have a small question to you. If you have a pain in the chest or your throat hurts, do you go to someone who claims to know everything about chests and throats? Or you look first if the person has a physician diploma? IS CERTIFIED.

Certification does not give you either you are an employer or just need a consultant, a guarantee that you will get the best professional available. It does guarantee that the person you talk with is a professional in the required field.
An ISO certification, as an Auditor or an Implementer and shows you that you have a person above the minimum required to perform the task you need and even more, he is continuously improving his knowledge and experience as proved by the periodical renewals of the certification.
PECB, one of the largest certification body for persons makes all the efforts to ensure that those persons answer the expectations.

Getting such a certification, from a well-known organization, helps you, the EXPERT to be in the first line of consultants considered for any desired position.