Tom, most of the NAR designation classes don't have applicable knowledge for me. I didn't learn anything new or useful in any of them really though I'm not a CRS. I do have SFR, ABR, ASR, whatever the relo one I got is and I feel like I'm leaving one or 2 out. They are probably good for new agents that have no working knowledge but for any experienced agent I just don't think they offer much. I've invested a lot in my education as a Realtor. The best courses I've taken were Acceleration which is fundamentals of real estate sales course and Top Gun which is the advanced Acceleration (3x-twice by the Training Academy, once by Dirk Zeller himself). The other really good course was a generic course on selling to personality types that wasn't even a real estate course.
Scott Kenkel's short sale boot camp ran circles around SFR.
Now that I've done all that I've had a personal coach which has taken me to the next level (John Gualtieri who was a top 10 agent for Re/Max for many years and is now a full time coach). If you want to see what he does the link is here:
Mega Agent Maker - Real Estate Training and Coaching
Nothing NAR has offered has even come close to any of that. As you can see I'm a believer in continuing ed, but only when it's worthwhile. NAR's is a joke put together by a bunch of suits that probably came from marketing and never sold RE a day of their lives.
As to your comment about agents with designations being more successful, well I'd say it's because they invest more in their careers and care enough to try and improve. They are better because of their efforts, not the designations. I've been on roughly 85 listing presentations this year and not one of them has asked about designations. I'd conservatively say I've done 750 presentations and have yet to be asked about designations. I can't refute or confirm your claim that the public cares but anecdotal evidence says they don't.