True...but getting stuff in and out of a backpack is not easy. Backpacks are great if you are GOING to a location and want to unpack there...like you are going to the library to study. Backpack might work if you are going to go on a walkabout for the day, but I think getting in and out of the car, accessing your iPad from time to time, you still need something else.
My litmus test is this...I am standing in line at the return counter at Best Buy... one of the worst in town...and almost always a 10-20 minute wait just standing there...although Walmart was so long the other day, I left the line and went and shopped...came back and it was still a 20 minute wait (ok, I return/exchange a lot...sue me...but it could be the doctors office, or sitting outside a store while the wife shops, take your pick).
How easy can I whip out my iPad? It it is in the backpack...not so easy. If the bag has a flap over, still not as easy, at least not to jam it back in the bag. It has got to be easy to access...really easy to access.
+1 on the backpack.