I use it every day, almost all of the time. I don't use a lot of it, but what I do use is tremendously useful. My workflow is usually:
1. Navigate to the folder in terminal (old habit, or starting servers) and type in `github .` which launches the client for this repo.
2. Sync to pull in new changes (cmd + s)
3. Create a new branch (cmd + b)
4. Commit as I code (visual diff helps me do light code review on the spot). This is definitely the core usage for me — seeing what uncommitted changes I have, selecting out partial commits, drafting up good commit messages, amending bad commits, etc.
5. When I'm ready to publish my branch, sync again (cmd + s)
The key for me really comes down to some really simple stuff: a visual editor for creating commits, and quick keyboard commands to common actions (branching, switching branches, push/pull). It's possible to do fast in terminal, but muscle memory serves me personally much better with real keyboard commands.