all kindle apps are unrestricted and you can read as much as you want. the motivation for buying the actual kindle is, as the guy above says, that it is a superior device for reading, which is true.
i have both and the kindle is superior. with the ipad I find get distracted at shiny objects and end up not finishing a book. plus i dont sweat leaving a 50 dollar device lying around than an 800 dollar one. wait, this has nothing to do with your question. see how distracted i get. amazon is like google. they figure the more people they reach with their reader, even at a loss, the better. in the end it pays off and they are correct. plus they have tons of advertisers. people with kindle apps will buy kindle books. its my preferred format. i use calibre to manage and convert them from epub or pdf. great program.
i ahte both of you two. we all hate everyone. but back to kindle talk. i bought a kindle fire. i sold my hp touchpad on ebay for twice what i paid for it. so with that 200 i bought a kindle fire. primarily the reason i got the fire was that it run android apps. the hp touchpad was terrific hardware, but the OS is limited by a lack of apps. i want to play words with friends on my tablet. also if you happen to know my first and last name you can play words with friends with me, because it is my username. if you dont know my full name we are not that close and we shouldnt play.