This really isn't an issue for me personally. Whenever I see those focus group commercials for ... Verizon, maybe? ... that show the focus group choosing the network with the "most 4G coverage" I wonder whether those people really need it. If you live in New York, why would you care whether there is 4G coverage in Laramie, Wyoming or Tulsa, Oklahoma? Makes no sense.
As someone that does travel a lot, but tends to always be in a big city, I've never had a problem. I use a GPS running app and Spotify for music when I run nearly every morning, wherever I am, and it works every time. That's why I haven't bothered to downsize and transfer my iTunes. Just my personal experience, mind you. The photos seem to find their way to my Mac laptop iPhoto app and my virtual pictureframe at home magically via the cloud. It's pretty cool.
Thanks for all the explanations on SD though. Makes sense. I personally haven't needed a lot of storage, but I could see why someone would want the option.