Non DRM Mobipocket format is already supported on the Kindle - just drag and drop.
The hack allow ENCRYPTED Mobi files to be read on the Kindle. So you can buy a DRM-protected mobi book and read it on Kindle.
DRM is not to prevent other files from being readable on the Kindle.
The Kindle is already able to read more than just Amazon DRMed content, it can handle a number of formats.
A revolutionary portable reader that wirelessly downloads books, newspapers, magazines and blogs to a crisp, high-resolution electronic paper display that looks and reads like real paper, even in bright sunlight.