My biggest reason for canning rather than freezing, is lack of freezer space. I make our breads too, so the freezer fills up quick, even if the soup doesn't take up much space per bag, I make it in large batches (8 qts of broth each time). In an apartment kitchen, every inch counts!
It's also nice to have homemade soup to give to others, without worrying about spoilage. This was my first try at canned soup with meat in it. My veggie soup is a favourite among my friends and family.
I may try it with chunks next time around and only add it to a couple jars to sample it.
Who needs exercise when you cook with cast iron?