For the most part it is a recognized credential that shows you worked hard enough and were smart enough to obtain it. Success getting these credentials often translates to success on the job.
Another way I frequently see people obtain success is through family or personal relationships. People get their family and friends hired even though they don't have any degree or experience.
Not a lot of fun to see someone's 22-year old daughter hired into the firm as a "Network Engineer".
But the economy is tough now and the power resides with the employer.
The good thing about having independent credentials (vice being related to someone) is that you can change jobs. The credential goes with you.
Ken300D