Having access to documents stored on Amazon is handy, but iPhone, iPad and iPod Touch owners will find little reason to begin reading their newspapers and magazines through the Kindle app [iTunes link]. That's because:
1) They're likely already paying to get access to their favorite newspapers and magazines on those devices, or getting them for free as part of their print subscriptions, and therefore have no incentive to pay for a second subscription through Amazon.
2) Most major magazines already have designated apps for the iPhone and iPad, and those apps (in most cases) offer a superior user experience. They're optimized for both screen sizes, and come with a host of bells and whistles -- links, slideshows, audio interviews, interactive graphics -- that aren't available in the Kindle app version.
Take a look at The Atlantic on the Kindle iPhone app, for instance, which has no navigation and virtually no formatting. Leading images sometimes bleed into the text of the previous story, and bullet points, italics and font sizes aren't rendered at all:
And here's Popular Mechanics on its iPad app (left two images) and on the Kindle iPad app (right image). Note how the story has been divided into two pages on the magazine's iPad app (left) to make it easier to read:
The update will be useful to one very small subset of users: Those who already subscribe to newspapers and magazines through the Kindle Store, and would like to have their periodicals synced between their Kindle device and their Apple devices. Those users can now take in a few pages on their iPhones in line for lunch, and pick up at the same place on their Kindle Fires at home, for the price of two subscriptions.