When it gets down to it, all computers "do" is 0100101101. Everything beyond that is a layer of "gloss" to make it easy for humans to use computers. Initially it was merely representing the binary in a higher form such as octal. Then came mnenomics so you could program "ADD" instead of 024, then labels and sophisticated assemblers. This was all for programmers, end users didn't get involved.
Initially, outside users had to make do with terse commands per above. The "glossy front end" evolved slowly, starting with more interaction -- breaking the command string down into questions, first with codes, then full literals. Errors got more descriptive. Typewriter interface evolved into screen interfaces. Later, typewriter "green on glass" evolved into GUI.
It depends on the application. Frankly, I use an old (30 years) command interface editor for much of my work and am very happy with it. I also use GUI interface when needed.
On a traditional 'green on glass' screen users often had to have a paper "crib sheet" with codes for various entries (a common one is US postal codes for states). But on a GUI screen a drop down menu can provide the codes and meaning and allow quick selection. I think that's a powerful advantage. GUI screens can also have a descriptive block for each field having special instructions. GUI screens, using different type sizes, can highlight important data, and show graphics.
Many professional programmers have no idea how computers work, let alone end users.
The real question is how much does a user need to know about the internal workings of _any_ machine? Years ago cars had choke controls and manual transmissions. They're mostly gone -- do users still need to know about them? As a motorist, do I need to know how fuel injection works? If the injectors get clogged, I have no idea how to safely clean them or even how to access them. Do I really need to know?
I do think it is helpful for end users to know a little bit about what's under the hood. But sometimes a little knowledge is dangerous. How much do they need to know?