Github for Mac is much easier to use than the Git CLI. Something similar to Linux would be great so I don't have to explain the weird Git commands to everyone who wants to do a quick contribution.

frankly, I have no idea, but win/mac users love to app-everything and except people with IT background, if you can't install and click on something it's like it doesn't exist. linux community is a bit different, and when you narrow the target: using linux + using git + using github, the probability he needs a desktop client is very low and it wouldn't get so much traction.

I work on linux and I often use gui tools for my hg/git repos, but it's eclipse extensions where I do my code, I can't even think of a use case for a standalone gui app.

I've had a few situations where I found it easier to review commits, retag, and merge from `gitk`, which sadly has a very confusing UI, over the command-line, where it's difficult sometimes to keep mental track of commit trees.