Yes Amazon are trying to have more control over what you do and how you do it - with the view to getting you dependent on them and giving them easier access to your money.
If you can't bang a few books on to an SD card and read them, then that's one less way you can avoid buying books from Amazon.
I love the Cybook as you can just drag and drop stuff, use the SD card or not, without having to install any pernicious software. Same reason I have an iPod alternative - wouldn't touch iTunes with a long pole.
