As you know I've been a fan of 9mm revolvers, and auto cartridge revolvers in general, for decades, and have read about everything I could find out them.  I've owned three 9mms and a couple .45s myself, and have talked to a lot of people about them.  My hopefully semi-educated opinion is that the general shooting populace doesn't want to mess with moon clips.

In previous times, not even so long ago, moon clips were thought of as antiquated, a way to make old government revolvers at least somewhat convenient.  In the last decade and a little more, moon clips have become first popular and now standard among the more dedicated competition revolver shooters shooting standard revolver cartridges, mostly .38/.357s, as their speed was recognized.  And only in the last few years, some 38/357 revolvers have come from the factory set up for moon clips.  Mostly still S&W Performance Shop offering, the competition cognoscenti realize the benefits.  That said, they are still mostly lost on most defense-minded revolver shooters.

I think the problem is because of the nature of defensive revolver shooters.  Except for a few savvy gun guys, the majority of people choosing revolver for main guns are not gun people at all, because semi-autos rule the defense gun world, and we both know it (right or wrong), and they wouldn't recognize a moon clip, much less understand the benefits.  Now there is a lot of small revolver use as back-ups, but that group is, demographically, an older one, again one who never really thought much more of moon clips than as a way to use that old Model of 1917 sitting around. 

I think that this generally explains why S&W, Ruger, and Taurus have all made several 9mm revolvers over the years, and why S&W has added 10mms and a .40, and why they have all been financially unsuccessful.   The small number of shooters really seeing their niche is a small one, and not enough to sustain sales. 

S&W tried the clip-less model 547 and that failed mainly because it was fragile according to some.  I believe it failed because people weren't interested in a medium-frame 9mm revolver at that time.  I don't know how hard they tried to sell it in Yerp but that was their market if there was one.  I do understand that Ruger did better with their moon-clip Service and Speed-six 9mms in Yerp.

So now we have Charter Arms entering the auto-cartridge revolver business.  I think it is because they came up with a good little design and decided to market it.  If they can overcome the damage to their reputation done over the course of the 90s by "Charco," they could succeed as a lot of people still like a small snub as a back-up gun, and their prices are right.  Lots of people will forgo a little quality to achieve a good bit of savings, but many fewer will forgo any pretense at quality, and Charco had none.  And precisely because most people who would buy a Charter Arms revolver are not the same people who realize that moon clips are actually better than speedloaders, I'm predicting that success depends on CA getting enough guns to market on a steady basis.

...their cartridge retention and extraction system is cool but is it needed?

Is it needed?  I think simply yes or no would leave too many questions unanswered.  They think it's needed, and I think I follow their reasoning.