Depends on how well-designed the app is. GitUp has been my go-to for years, after trying almost every other app out there. It offers a bunch of powerful features exposed mostly through right-click menus and single-button shortcuts. The only reason I ever go to the command line (and I used to be a religious command-line-only Git guy) is because GitUp freezes on extremely large diffs, which one of my projects has a lot of.
GUIs are discoverability nightmares though, as you describe. CLIs are the only place you can do a “man git | grep thing”. On macOS there’s ⌘ + ?, but that has never covered all the content in a man entry for the related CLI, IME.
