It probably poses some benefits for terminal beginners, such as helping designers use git for instance in a UI more welcoming than the standard term.

I see this attitude all the time, namely the idea that difficulty is somehow proof of quality, or "professionalism" of a tool. It's obviously rooted in some instances where it is/was correct, such as the superior typesetting of LaTeX vs Word for academic work. But it's not an ironclad rule, and it shouldn't be trotted out as an argument anytime someone tries to improve existing tools. In this case:

- I'd say I need to look up any option flags or commands I use less than 15x/week

- Even the most professional 10x developer will spend a significant amount of his time with such commands, making this feedback useful

- The shell is essentially a REPL, but most people forgo most of its potential because the language isn't core to our work, and somewhat hideous. Anything that helps discoverability could be useful.

And, for what it's worth, designers that work with code usually don't have problems with git. Designers that work with photoshop would rarely need git, which is kinda out of its element with binary data

Emacs has had both shell completion popups (via Helm) and a better git UI (magit) for a number of years now.