So the author wants people to use dropbox over git because a repo takes too long to set up. Then their idea of version control is to copy files out of dropbox to somewhere else at random intervals. What on Earth...
butwhy, I understand the confusion, but I believe the intent of this suggestion is to not burn time trying to get people who have not been exposed to version control systems up to speed with git. Recently I've been working with people who are not professional developers and realized that even with a good front end like GitHub, VCS is a rather large concept to absorb.
While the benefits of VCS far outweigh the work to grok the ideas, the rate of return may not be high on the small timescale of a day or afternoon at a hackathon that is aimed at interested but relatively green individuals.
Given github has a desktop interface that is super simple and easy to understand and can be explained in a single sentence, I am not sure there's any reason to not use it.
It kind of reads like the author doesn't know how to use git... In no way shape of form would I use Dropbox as a repo.
I have however had experience during a hackathon with a team member who was doing some HTML stuff who didn't know how to use git. I opted to just do the merges myself manually, never would have even considered moving my code to Dropbox.