But it makes complete sense.
If you could maintain the same character and switch servers at will, you could capitalize off of the server's differing economy. Soon enough, everyone is going to start buying from the server who's prices are the least, and this will result in the price rising. They will then move to other servers, and the same thing will happen, until the process keeps repeating itself until every server is selling *wark* for more than it should.
I admit, I didn't like the idea at first either, but this reason, and more that I have thought of in the past but can't remember, are legitimate to the whole server issue in my opinion.