Or someone like me who reads often, and at great volume, and wants to read more. Not everyone is like you.
Reading a couple of books weekly, and switching between these reading styles, also makes me think the reading speed should be set per book, not as a general setting. If you're reading Tolkien at 250 words per minute and a fast-paced paperback at 450, you shouldn't have to adjust the speed every time you pick up a different title. Since it already tracks where you are in each book, remembering the reading speed for each one seems like a logical next step.
Anyway, that's a really helpful point.