Hmmm....I didn't think I needed one, until I lucked onto a good deal for a Winchester 94/22M XTR in .22 magnum. I had fired a very few guns in the caliber, but owning one, and plinking with a buddys gun are two different deals!
At least in the Winchester, the .22 magnum is marvelously accurate. Also more destructive than I thought! True, ammo is a bit pricy, but then most ammo is pricy these days.
The Winchester is a classy gun, and I'm sure it adds appeal to the caliber. I remember a couple years ago, wishing the 94/22 was chambered in .22LR instead of magnum, while I paid for the gun. Not so now, I'm quite happy with the chambering. Ammo is easy to find, caliber is nice for longer range plinking where a .22lr is falling off, and frankly, I like it better than my .17HMR.