I wouldn't use a 22lr pistol either, . . . . unless it were a last resort type issue.
As for Velocitors and using 22lr for defense, . . . I would actually be fairly okay with that setup. . . in an AR style 22lr dedicated rifle. I don't HAVE such a setup, but would feel okay with it. 25 rounds of Velocitors in a carbine length, low recoiling platform could put a lot of hurt on someone [if I ever felt the reason TO point such a rifle at someone, and hope I never have to, needless to say].