I dry fire my defense guns, but not my .22. My reason has nothing to do with whether to dry fire a rimfire. I bought a .22 for cheap trigger time, to provide a bunch of repetitions that would largely translate to increased skill in shooting my defensive handguns. I dry fire to provide not only cheap (free!) repetitions, but to be able to practice on all the other days I can't get to the range. This, too, is to hone skills that will translate to shooting my defensive handguns. So if I'm dry firing, there's no need to use the "substitute" pistol; I use the "real" one.
But if the .22 is THE gun you're trying to develop skill with...
"An armed society is a polite society." Robert A. Heinlein
"After a shooting spree, they always want to take the guns away from the people who didn't do it. I sure as hell wouldn't want to live in a society where the only people allowed guns are the police and the military."
William S. Burroughs