I use one or more GUIs for visualizing branches, and old branch cleanup, and yes, committing single lines from hunks that can't be split.
However for everything else CLI is fairly close to optimal, including interactive adding/rebasing, and don't want to use whatever shitty editor your tool has in it, I want to use vim with syntax highlighting so I can properly format my commit messages. Even something as simple as viewing a full commit is faster in the CLI because you can just pipe it to less or send it to an editor versus whatever tradeoffs a GUI has to make to stay performant, make use of screen space, etc.
One last tool is Fugitive. This blows away anything else I've ever seen for interactively traversing history at the line level.