If you're using a GUI, that means whatever you're doing you're not doing a lot of it, since you don't need to automate it. I would expect a world-class enterprise engineer to be able to automate most tasks, and from that they would be very comfortable with the command line.

Can you do everything with a GUI that you can on a command line? Yeah probably, if the developer is at all the features properly. Can you automate it easily? No not at all. So the more you do something the more you tend to want to deal with the vocabulary of the command line because it's more expressive and allows for automation.

I will die on this hill!