I cannot reply for that person, but to me a certification would mean that you know a given subject, so I could ask more in-depth questions and expect better ans

I cannot reply for that person, but to me a certification would mean that you know a given subject, so I could ask more in-depth questions and expect better answers than the average candidate. Sometimes this is the case (and if so then getting a certification is not harmful in my opinion), but often it just gives you a very high level, very passing understanding of the subject so candidates just end up being judged against a higher bar without the tools/skills to match it.