Have you ever seen anyone struggle to even use an iPhone? I have. These interfaces aren't completely natural enough for everyone to grok. As I stated, I saw a potential use-case with the illiterate - tech or otherwise. I think this is valid reason enough, but not everything has to be some major innovation vs the previous one.

This is a startup and tech community. What's the point of Dropbox when "you can already build such a system yourself quite trivially by getting an FTP account, mounting it locally with curlftpfs, and then using SVN or CVS on the mounted filesystem"?

Just because there's alternatives doesn't mean this product doesn't have a space in the market.