Many years ago my cousin lived in Colorado and his next door neighbor was John Denver, but he never saw him, they lived on different mountains. My cousin had a .460 Weatherby Magnum he carried when he went out on his property, not with the intent to kill something, although he did hunt deer for the meat, just not with the .460 Weatherby Magnum. He carried the .460 Weatherby Magnum just in case he ever ran into a Grizzly bear that was not all to happy with his presence. While he lived there he did come across a Grizzly but luckily he never had to use the Weatherby.
There can be other reasons to own these guns than what they were intended for. However I do not think I would go get me a .460 Weatherby Magnum for target practice.