The iPad is very similar. Yes you will not type a manuscript on the touch screen. Will people spend half an hour poking around links on Zappos while watching TV? I think so. Is it any harder to hold than a hardcover book? No. Will the occasional moments of interaction be any more burdensome than a large newspaper? heck no.
Think about how much navigation you can do without typing. I could plow through twitter, gReader, a couple news sites, an ebook chapter, all without needing to launch a keyboard. And thats what people will value.