A more pragmatic concern

Another good question: Why would I want to access programs and documents at the painfully-slow speed of 4 kilobytes per second when I enter an area of bad 3G reception? I live within a 3 "broadband zone", but more than half the time the modem drops back to dialup-like speeds. And don't get me started on the ability for 3G networks to lose packets and cause a large download to fail (or force you to click the Reload button in the web browser).

3G is good for accessing the internet when you're on the run, but it's freaking terrible for running your whole computer from it.