I want to clarify why I do not use my Kobo as a device for buying books. I buy lots of books from kobobooks.com, that's not the issue. The issue for me is that buying and reading are two different activities. When I seek to make a book purchase, I'm not buying to read the thing right away. It's a purchase for future use. When I'm reading, I don't (all of a sudden) get the urge to buy a book. I'm reading one that I'm invested in at the moment, and that's all I'm interested in doing.
Besides, It takes me forever to find an ebook I want to purchase. You can't just return the ebook for refund if you're dissatisfied (generally speaking), so I try very hard to figure out if the author's writing style suits me, and if other people recommend it, and if I'm willing to take a gamble on the publishers' quality control (because I really hate terribly formatted ebooks).
I used to walk into bookstores browse books and buy some on a whim. If I didn't like them I would just pass them off to someone else. I can't do that with ebooks (not legally, anyway).