The CLI is scriptable/automatable and unambiguous when sharing instructions with coworkers. Both of these things make it very useful to know the commands. I do agree that it helps in some situations to visualize what is going on with a GUI/TUI though (neogit for nvim or magit for emacs are great if anyone is wondering), it can make things clearer at a glance.
I would argue that the same things were probably true in western capitalist countries at the time (I have no evidence)