title_body: What are the benefits of Amazon Kindle device over Amazon Kindle app for a power user? Are there any benefits to reading e-books on Amazon Kindle device over reading those same e-books on Amazon's Kindle app on a smartphone/tablet, for someone who is a power user?
  
  I'm excluding the obvious hardware differences (e.g. Kindle had bigger scree size than an average smartphone and has better battery life; and presumably Kindle's screen is easier to read books on).
  
  What I'm interested in are features that are open to Kindle device users, that aren't easy to recreate/achieve on an Android device.
  
  As an example, may be some e-books are exclusive to Kindle devices (permanently or on launch). Or some features of Kindle device software aren't present in Kindle Android app which can't easily be replaced.
upvoted_answer: Lending only works on Kindle devices, not the apps. Specifically, there are two things that Amazon lets you do only with Kindle devices. First, Amazon Prime members can "borrow" books from the Kindle Library, which includes lots of bestsellers and older books, but only on Kindle devices. Second, users can lend many (but not all) books to other Amazon users. But, the recipient can only accept and read the loaned book using a Kindle device.
  
  Other than that, I don't think there are any advantages to the Kindle 3G over reading in other contexts. I do 80% of my Kindle reading on the iOS apps, about 19% on the PC app, and the remaining 1% on my actual Kindle.
  
  With a Fire, this is less of an issue, since it is much faster, prettier, and more full-featured than the older Kindles.