As to whether a 22 is a useful training tool:
Certainly, in an ideal world, we would train with the same caliber firearms using the same full-powered ammunition as we expect to use when we fight or hunt.
It is not an ideal world. Every Winchester Silvertip, Speer Gold Dot and Hornady TAP round that we fire downrange at a piece of paper is one less that we have at our disposal when we need it. Ammunition is expensive, and it is scarce. But our skills will degrade if we don’t hone them with constant practice. If you are magnificently wealthy, or have procured a reliable source of cheap full-powered ammunition, or if you are a competent handloader, then perhaps you don’t need to be so frugal. But for the rest of us, blasting away with full-powered ammo is the equivalent of turning money into noise.
It’s generally acknowledged that dry-fire practice on a daily basis with your carry handgun is the best way to keep up your skills. Draw and snap. Draw and snap. But we tend to get bored and lazy. It’s not “real” so we don’t take it as seriously as we should. How much better if we were able to draw and BANG! instead? A .22 pistol that is identical to your carry weapon will allow you to practice with immediate feedback of your strengths and weaknesses, letting you maintain familiarity with the weapon, for only a few dollars per day of rigorous practice.
The next best thing, of course, is an airsoft pistol that is identical to your weapon. The best things about this are that you may practice indoors, and with suitable eye protection even train force-on-force with a similarly-armed opponent. That will give you an immediate and sometimes painful reminder of what you might need to improve on in your technique.
Don’t dismiss the little .22. Better to shoot it often than to shoot your “real” weapon only seldom.
