I have to agree with Cholla Hill's second line here about the small caliber.
I did not mention the combo gun factor in the original posting because I do not see the two firearms going together as they would with a 44/40 or 38/40 cartridge. Now the two larger cartridges were more often used by lawmen, bad men and just travelling men IMO. That means someone on the road or country that had to kill a lot of game (not knowing what type of game you where going to cross) to stay alive for long periods, without town visits. I do not see someone like that depending on 32/20 to stay alive and also desire a handgun of same, for convenience.
To me, the general term of 'handgun hunting' was not as common at that time, as it is now. Yes, Keith was experimenting in the '20's but not too many 'working people' would just buy a handgun to 'try and shoot game' for dinner. Nor would a rancher or ranch-hand depend on that caliber for shooting coyotes, wolvs, and/or mountain lions, to save livestock.
So my question still stands Why in about 1884 to 1940 did Colt produce ~30,000 - 32/20 that shot a 115 grain bullet at ~760 ft/s and who bought them, for what use?