Brilliant for you, yes. But when does amazon begin to consider this a bug, not a feature? I worry for the day that some new feature is introduced in .azw files that will break legacy devices. Now that would be evil.
Amazon are looking to make money off the books, not the device (they're basically the opposite of Apple). The Kindle device price is trending towards zero - a lot of good money is betting that Amazon will eventually give it away for free, making all their money back on book purchases.