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.
Ebook readers have extremely high contrast/readability and are extremely energy-efficient, being able to display several thousand pages of material without needing to recharge. eBooks are a narrow product, but they have their own ways in which PMPs cannot compete.
DRM is not to prevent other files from being readable on the Kindle.
Granted the PDF converter seems to have some trouble with graphics PDF's, but for books the converter works very well.
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