I think that traditional bows manage to fall in to several categories that make them very tempting, desirable, and rewarding to own more than one.
First of all they are amazing and ancient tools that are a conduit to our experience of the natural world and can connect us with our heritage. They then become symbols of our outdoor experience.
Second, they fall into the "man toy" category. I mean come on, they shoot projectiles, are made of wood, look cool, have power in them, can be used to kill animals, and feel great in your hand etc...
Third, like mentioned above, they are hand made art. And each bow represents a lot of skill, effort, design, and craftsmanship. This is contrary to many of our possessions these days which are made quick and dirty in a far away and anonymous sweatshop factory. Plus, they are mostly made in the USA! And you can actually talk to the person that made them! How rare is that these days?
Fourth, there is the "but I might need it some day" category and the "but the deal is so good" category.
There is also the "neglected treasure" that needs to be discovered and saved from the junk pile in someone's shed. How can you pass a good one up at a garage sale if you know that it might never be appreciated or taken to the woods?
Finally, there is the collector mentality. Trad bows are a perfect item for collectors. Each one is unique and has it's own story. And they look great displayed on the wall.
I'm sure there are lots of other reasons too.
Maybe we can make a list of reasons to use to explain to our wives, girlfriends and families why we need more bows