The former. A tiling WM covers the entire desktop with whatever windows are visible in the workspace. One window starts out full screen, creating a second window halves the first one and tiles them side-by-side, and so on. I would only see the desktop when I switch to a new empty workspace, but the reason I switched to a new empty workspace in the first place is because I wanted to start a new window there, so that glimpse of the desktop would be short-lived.

Many tiling WMs have an option for gaps between the windows. Do you find them unpleasant? I love my 8px gaps. Most of the wallpaper is still covered, though.

I personally hate those gaps. Wasted space.

Maybe these gaps should be filled with decoration. Like with ornaments similar to those you can find in medieval books.

To each their own. <3

Oooooo, window borders that look like an illuminated manuscript?

I need this before I screenshare into my next Teams call...

I agree. For me the point of a tiling window manager is that it efficiently uses the screen space automatically. I don't have to drag windows around to do it.

Automatically wasting space sounds less attractive...

Tiling window managers generally size windows as large as possible. Windows only shrink to make way for other windows, so unless you do something weird, or switch to a desktop with no windows, or have some sort of transparency enabled, you won't see your background at all.