The main point is that Amazon is not playing nice in terms of a unified, industry-wide format (ePub) OR with libraries. If you can live with the inconveniences that creates, good for you.

But we have a lot of patrons come in and ask why they can't use their Kindle with the library's ebooks. Setting aside the DRM issue, it's all because Amazon chose segregate their format from everyone else. Not everyone is tech savvy enough to figure out how to convert a book.