Actually, for most people (don't forget that the bay area isn't the normal world) -- the cost/benefit ratio is definitely there. Just read the reviews, from all the top reviewers. People know how to upload photos to their computer. It's not rocket science. But they don't do it because it's a chore and take a lot of activation energy. So like any other chore out there -- they end up putting it off.

With the Eye-Fi Card, all you do is get in range of wi-fi, turn the camera on, and the photos will go to your computer and to any of 25+ sites. It'll also tweet on your behalf, and embed geo-location information into the EXIF header.