We say "chicken and egg" in English
. Yes, I understand what you mean, but for me, the iPad can replace both a netbook and a bookreader for travel. For example, I've been using my iPad at work for two full working days and, and starting a third now. Checking my e-mail roughly once an hour, reading, etc. The battery is currently at 68%. Switching off WiFi if you're not using it at the time does dramatically increase battery life.