Where the iPhone conquered your pocket, the iPad will conquer your backpack.

So says Tim Carmody on the Snarkmarket blog, where he puts down his thoughts about why e-books on the iPad will be more successful than some people think.

Carmody starts with five common reasons skeptics give that e-books won’t take off on the iPad, and notes that most of them aren’t all that new. (Though he does not address the oft-heard complaint that people will not want to read from LCD screens.)

He points out that those who buy the least expensive, 16-gig wifi-only iPad model will, unless they are somewhere with wifi, be limited to what they can carry on the device to read or watch—and 16 gigs will not hold a lot of movies but will hold plenty of e-books. He adds:

(This is actually why I suspect plain-jane, text-only books are going to have a long life as the de facto default for a while. Dedicated reading machines like the Kindle or Nook can’t support anything else, and more versatile portables like the iPad don’t have the built-in memory or everywhere-internet to support a whole library of these things. Add our inertial devotion to document formats like PDF and it may be a very long time before multimedia books or magazines become main­stream items.)

Carmody uses video games as another example of why people might try e-books. He writes that he had never been a mobile video gamer before he bought the iPhone, and indeed bought it mainly as a phone and portable Internet device. But since he already had the device and they were available, he eventually went ahead and bought some iPhone games, too.

And Carmody thinks people will be exactly the same way about e-books on the iPad: they might buy the iPad for surfing the net, watching movies, and playing games, but sooner or later they’ll be in a situation where they need something to read and figure they might as well give it a shot.

This idea is not exactly a new one. In fact, it is probably responsible for the first popular emergence of e-books, back in the ‘90s, as a number of people bought Palm Pilots mainly for use as personal organizers but discovered they were marvelous for reading e-books as well. Of course, it still took over ten years and major e-tailer involvement to kick off a widespread adoption of the format.

As I mentioned above, Carmody does not touch upon the perceived eyestrain factor of LCD screens as opposed to e-ink for reading. I personally think that once people actually have iPads in their hands, they will find it largely a non-issue as long as they remember to adjust the brightness to an appropriate setting for their environment.