A few weeks ago I purchased a Ruger SR22 for my wife's birthday present and as a training gun in my firearms training classes. I try to train my wife on my 9 mm pistols and she has made modest progress with them but is somewhat "recoil shy" no matter what I do to try to help her overcome that issue. Once she shot the SR22, she nearly got angry with me for not exposing her to the .22lr pistol sooner. She has shot our 10/22 rifle with good results but has never handled and shot a pistol less that .380 cal. She had tighter groups and faster follow up and thoroughly enjoys shooting her Ruger SR22.
I was recently giving a lesson to the wife of a good friend. He had just purchased her a Keltec PF9 (did not consult with me...). No knock on Keltec, I know there are many satisfied Keltec owners, but the gun was malfunctioning right out of the box (bad extractor) and she was not enjoying her shooting session. I could tell she was having recoil issues, as do many new shooters. I took out my wife's SR22, gave her a good orientation on the operation of that pistol and within 20 minutes she was shooting 6" groups at 7 yds. She turned to her husband and said, "I want you to take that gun back (PF9) and buy me one of these (SR22)."
I explained to her, as I did my wife, that my goal is to work them up to a 9mm, slowly and at their own pace. Now, do I think the .22lr has a place as a defensive weapon? I'd have to answer "yes, under certain circumstances". I feel confident that either of these ladies would be able to defend themselves with the SR22 with a fair degree of confidence in their abilities. Do they both need more training and practice? Yes. But who doesn't?