I have owned a Marlin .22 mag for many years. Bolt action model 783. I mounted a Weaver K4 on it in Weaver rings.
For some 20 years, I have taken squirrel, rabbit, turtle, birds, and assorted varmints with this rifle. It is reliable and accurate, though I do not often even try a shot past 60 or so yards. I have taken a few crows at over 150 yards, and the Winchester HP did what it was supposed to do.
Any reason to own it? Not really, but I do, and I like it. I think that this is the 'reason' a lot of folks have a specific caliber or gun, they just plain "like it".