Bear in mind, though, that I'm talking about well-designed certification programs, ones that are not just granted for theoretical knowledge but instead those that incorporate lab work to demonstrate that the certificate holder has mastered the subject both in theory and in practice. I think those kinds of credentials are good for employers, good for employees, and good for vendors. From an employer's perspective, certificates can provide an easy way to identify qualified candidates. A company can also use certificates as incentives. The prospect of a paid-for certificate might be just the carrot you need to retain skilled crew members, especially if bigger bonuses and longer vacations aren't an option.
Certification programs benefit employees, too.
I can say from personal experience that employers value certificates, and right or wrong, you often won't get the job if you don't have the right piece of paper. But most IT-related certification programs are just schemes to lock companies into a given vendor's proprietary technology. That's why I'm against them. Things weren't always like they are now. There was a time when certificates existed primarily to let workers advertise their proficiency in a narrowly defined skill set, as in WordPerfect proficiency, for example.