Availability of ammo is a legitimate concern with the .32's, IMO.
When I was given a Single Six in 32 H&R Magnum in 1985 there were not many reliable sources of these shells in all of central KY. This got me started into reloading (THANK YOU!!!) for the round.
After the 327 was introduced in 2008, there was a definite lack of ammo for this round. However, there was a shortage for EVERY kind of ammo, especially 380ACP. Panic buying emptied the shelves of stuff covered in dust and everything else. The last 2-3 years, I have seen 32 H&R Mag and 327 Federal in more shops than ever before- Why? The LGS owner is not worried about it sitting there on the shelf gathering dust. There are enough guns out there to keep people shooting and buying ammo. Its one of those "self-fulfilling prophecies" where I am not going to buy that gun because there may not be ammo available in 5, 10 or 15 years... If enough people follow that logic, then 15 years from now we will all be shooting .22's, 9mm. 38SPL, 40S&W, 44Mag and 45ACP in our handguns. If enough people decide to buy the guns on their merits we will not be in that situation. Assuming I am still alive then (47 now & I know none of us are promised tomorrow) I will still be buying 327 for self defense.
You are not likely to find 32 H&R or 327 Federal at Wal-Mart or Bass Pro. It is out there at other locations. I have seen it on shelves in gun shops all over Middle TN.
As far as 32ACP, I have fired it in a Single Six. It is your last ditch option but it is an option. I would never recommend it. More like, "In a pinch, you could..."
my .02,
32Magfan