All things I know are possible. I understand Git's architecture, just like I know what an inode is. I could re-implement my own (bad) version control system, if I wanted to, just like I could make my own (bad) filesystem.

But that doesn't mean I need to have memorised the CLI invocations. There's a button in Git GUI for all the things I need to do (including the things you've listed), and in the rare case where I need to do something else (e.g. submodules), I can look it up, just as I do in the rare case where I need to make a symbolic link.