The .22M and .17hmr are cartridges I think are foolhardy in handguns
22mag in a Ruger Single Six is a great small game hunting round. It is a great way to train kids on handgun hunting. My first handgun hunting was with 22mag and I will do so wilth my children.
Also a snubby 8 round 22 mag could be a SD option for someone that is recoil shy and/or has trouble with semi auto slides. Not many light weight, low recoil options in a revolver espically with 7,8, or 9 rounds. The 22 mags fills this void (even if it is not a huge market)
I think it is foolhardy to discount the 22mag