Good list but you forgot the #1 reason someone might want to jailbreak an iPhone.
The iPhone is apparently a fairly nice hardware platform with good Internet connectivity. The only thing it lacks is a working web browser. Apple thinks you can have a browser in this web 2.0 age without the Flash plugin, Java, Acroread etc.
I swear, if somebody could get Adobe to license the Arm port of their plugin, bundled with one of the Moz based embedded browsers and have it 'just work' and sell it at a reasonable price it wouldn't matter whether it was in the official App Store or not. Apple would either relent and allow it to be sold or see half of iPhones jailbroken within a year.