The canoe is a specific pattern. The mirrored bolster shape (like a copperhead, but on both ends) happens to make the knife resemble a canoe, hence the name.
As for Case, the company is well over 100 years old, and, for the most part, American made (they've farmed out work in the past). They make and made knives by the thousands, so it's still possible to find knives that are many decades old that are in pristine condition. Some collect new Cases, some collect old, some collect both. Some focus on specific eras, some focus on specific patterns.
They're collectable, because, frankly, they're collectable. They can be valuable because people want them, and the fact that people want them makes them valuable. Plus, Case is an American classic. Like the Zippo lighter (coincidentally, Zippo owns Case now) or a Mason jar or a John Deere tractor. If there's one knife that exemplifies the honest American working class, it's a Case.
