Studying the design document [1], one sentence makes it clear why this project is needed and simply using the Dropbox client does not suffice:

> We can perform a compare-and-swap operation in Dropbox by using the "update" write mode with a specific revision number.

Since a Git repository basically consists of a hash-addressed content object store alongside a mutable list of references (mapping branch names to hashes of latest commits), you need a compare-and-swap operation on the reference list to update the branch reference when you push new commits. The Dropbox client by design does not do a compare-and-swap whenever a file is updated, but the Dropbox API supports it.

[1] https://github.com/anishathalye/git-remote-dropbox/blob/mast...