I use both dropbox and git for my home projects. I sometimes develop on my desktop, sometimes on my wifes laptop, and sometimes remotely on another server through ssh, and I don't want to commit/add stuff to the git index just because I move from one computer to another. I could do this with branches, but it's too much hassle when I just want to shut down computer.

So I work on a directory that is in dropbox, and in git, and I can instantly shutdown my PC and start writing code on the laptop. Commiting changes is a separate step. It's quite convenient. Also I can test the code by accessing dropbox public link (it's mostly javascript and static websites), and there's no separate "deploy" step - when I save a file on any computer the change is ready to be tested, always at the same place. With git I would need to remember to commit, and update before I test, or I would need to set up a test server on every computer, and depending on where I work I would need to access different address. The difference between 15 seconds and 0 seconds to test small change is VERY significant.