The .32-20 was very popular around the turn of the 20th Century for rifles people used to hunt small game up to deer, but in a handgun it never reached near any amount of success compared to others like .32 S&W, .38 S&W and Special, .44 Special, and .45 S&W or Colt. I'd attribute that to the requirement of a larger frame for the long chamber and bullet. So, much like what we see today with the .327 in the Ruger Blackhawk and GP100, people are very leery about the concept of a smaller hot rod .32 in a larger revolver that is better suited for a bigger caliber like .357 Mag.
That's not to say there wouldn't be some appeal for a .32-20 single action for CAS, but other than that the .32-20 has become a relic with little practical use today in a handgun.