I want to personally see one or see pics of a production gun, in the wild so to speak. I can easily understand them using a filler kit on the early pre-production or mock-up guns as they went back and forth on design elements.
Over the last year, I've been buying 327 Fed Mag and 32 H&R Mag ammo. At least in my case, I found many more deals on 327 Fed Mag than on 32 H&R Mag. The 32 H&R Mag was significantly more expensive and harder to find, which is unfortunate, as I think they are both good rounds.
Considering your comment, I now see the other is the 38 Special, not 357 Mag, so strength was probably a factor. My 632 is vented, so I wonder if another factor is recoil management. An all aluminum J-Frame might not be easy for many to control recoil. My 632 is stainless steel and weighs 25 oz, so stronger and heavier.