There's some minimul visual elements, eg if you choose the tabbed layout.

So the comparison for XMonad wouldn't be all of KDE or Gnome, but just how those two choose to decorate their windows. Eg their 'minimize' and 'close' buttons and window borders.

To be slightly more serious than my original comment was:

If you can rethink your UI in such a way that some things can become invisible, that can be a very ergonomic choice.

To give a better example: look at the bad old days of C and memory management via malloc and free.

One direction you can go into is Rust. Compared to C, Rust has a greatly improved user interface [0] for handling memory allocation.

Another direction you can go into is Python. Compared to C, memory management is basically invisible in Python. It just works.

Now, of course, Python gets to simplify its UI by essentially removing control from the user. But for many programming tasks, that's a good trade-off to make.

Similarly, iOS gets to drop the UI elements associated with manipulating windows, because it puts every app in full screen. (And XMonad greatly discourages you from fiddling with Window placement and layout manually; but has some less-intuitive less-discoverable means to do that manual fiddling, if you need it.)

[0] The user of Rust being typically called a 'programmer'.