At the moment, I'm just using all my cash to merch.
I'm only 60 defence, and I realized that my armor was worthless to me (since I don't use it all all, I'm more of a skiller), so I sold it all. I'm a lot happier now. =)
Rares are just a way to show off the wealth you have, and it's a common rule among humans that everyone wants something not many people have, if anyone at all. They're just sought after because of that principle.