I dry-fire the gun that I'm currently getting used to. The trigger is part of it, but the way you hold while firing also gets a workout.
When first I took my new BLR '81 home, the trigger was less than delightful, being a bit hard and gritty. - So I practiced dry-firing at a knot hole on the tree outside my shop, through the window three or four times a day, three or four dry-fires each time. After a couple of weeks, the trigger was much smoother, and I was adjusted too... I got used to how it worked and how to hold the rifle by then, and the crosshairs were right on target whenever the hammer fell.
Part of dry-firing is to call your shots. That's what Bell was doing, out in the African bush.
Now, if I ever have to shoot a knothole through the window of my shop, I know that I'll probably nail it, first time!
Seriously; The dry-fire practice with the BLR not only smoothed up the trigger, but also has given me a bit more confidence about hitting things with that gun, and taught me the best way to hold it for accuracy. It is intended for hunting, so confidence and proper handling is a big factor, there.
I dry-fire my shotgun too, a nice over/under and you betcha I use snap caps in that gun. Something about the way it sounds when I dry-fire it without a snap cap tells me that it needs them.
The manual to my Ruger Mk III says it's OK to dry-fire, but I try my best to avoid dry-firing rimfires anyway.