This is exactly right. I have both the keyboard case (bought it half price when the tablet came out) and just recently bought the Book Cover. I like them both, but the ideal solution is a dummy flap to cover the screen when you don't need the keyboard. The back of the keyboard cover is great and with the near-permanent attachment (at least for mine), I'd prefer not to peel it off each time I want to use the Book Cover.
Between the two, I'm tempted to sell the Book Cover and just keep the Keyboard Cover since it's not much bigger/heavier, and it adds some great functionality with DeX.