I'm getting one in my Mac Pro when I order.
I work from home. Home is out in the woods. Once or twice a year, we lose power due to weather issues. We have a generator, but it only powers the main house, not the office; so if the power is out for long, I have to move my computer into the house, where our wireless signal is strong, but ethernet plug-ins aren't handy.
It's a small, $50 insurance policy that allows me to stay connected when I wouldn't be able to otherwise.
Plus, I think it would be fun one day to strap that baby on my back and go to Starbucks.