E-readers (the generic term, since not all of them are made by Amazon) are very, very cost effective and easy to use if you know basic computer/cell phone skills. First, it is not the same as reading on a common LCD monitor at all, unless you have a tablet like the Kindle Fire which IS a LCD screen. (I have the Fire and do not get eye fatigue, but I am used to reading on my laptop a lot.) E-readers use a technology called "e-ink" which simulates reading an actual book page. It's really cool.
E-readers save lots and lots of space and helps save the environment in the process as well. Most books cost either less or the same as a paperback edition for the big titles. "Classics" such as from the Victorian age are free. You can make annotations and other notes if you so wish. You can even punch a word and have a dictionary pop up. Lots of libraries are going electronic now too, so you can use your card info to "log on" and check out books on your e-reader!
They're just like any other technological thing now as well. I remember when MP3 players came out and people swore they would never stop buying CDs because they liked the physical aspect just too much. Well, we know how that went. Books (physical ones) aren't going anywhere right now. I only buy my favorites in physical form now.