I agree that the certification alone does not mean you are adept at dealing with all the issues. I will say that I have been in HR over 39 years and only got my certification a little over a year ago.
Taking the prep course and using the materials did help me in areas that have not been my strength. While I managed Labor Relations, I learned things I never encountered on the job. The same is true in some of the OD materials.
The SPHR certification does mean that the individual has the knowledge necessary to be in compliance. Many organizations are desparate for individuals who do know the laws and regulations.
My organization values the designation as it would a CPA and it improves my credibility. I do recommend individuals who have been in the profession for 5 or more years sit for the exam.