To quote one of the happy snarks, "If you really wanted "JUST" a book reader, get the damn Kindle and stop whining like a little girl about how "oh, the iPad's too heavy.""
One of my main reasons was to get a book reader. NOT JUST a book reader. I also use the iPad to store movies,surf, listen to music, etc. All holding the iPad quite comfortably. But reading a book is a different experience. I never used an iPad without a cover, but whether one reads horizontally or vertically, holding it out for long periods is more tiring than holding even a huge hard-bound novel for the same period. It just is. And I do exercise, even at the ripe age of 64y yrs.
Calling people like me stupid for expecting better is not helpful. I'm a Mac fan. Over the years have bought Desktop G5, Mac Pro Desktop, iPhone 1 & 4, Final Cut Studio, Aperature 1,2 & 3, QuicktimePro etc.
And calling people like me "whiney little girls" or calling one's sexual orientation into question is just plain bizarre. My blessed Mother, upon hearing such anonymous name calling would call it cowardly.