Honestly I'm not aware of any common repo tasks that I could more efficiently complete via the command line vs gitup. There are good keyboard shortcuts for everything in gitup so most everything I do doesn't even involve the mouse.
Also -- I'm the kind of person who's always got a set of terminal windows open and definitely uses them often (almost never use Finder, hate taking my hands off the keyboard to reach for the trackpad). At this point -- I never reach for the git cli over gitup (except when cloning a new repo).
I'm using mac at the moment, and the awful window management (and inability to properly change it - all wm apps just handle resizing and moving within existing spaces and margins) just makes me more motivated to do everything in full-screen tmux, to simulate a decent wm - as long as everything is CLI-based!
(I tried Arch on it for a while, but ended up deciding the firmware difficulties - in particular the battery draining quickly and CPU running hotter - weren't worth it; I traded i3 for full-screened tmux.)
I used to use a GUI for git, but now I just find them cumbersome; by their nature requiring me to switch window for less.