I'd also note that it saves you from those dreaded days when a new iPhone or similarly expensive device is going to be left sitting on your doorstep while you're at work...
UPS/Fedex take all the risk when they do that. The driver is taking the chance in order to clear his truck. Unless you authorize it with a signed note, they should not do that. They don't do it in SF or NYC since your doorstep is the street.
This. This is the biggest issue in my mind. I would most definitely pay $7 to make sure they don't just leave my $700 new tech on my front step in full view exposed to the elements.