Yep, I like adding some space between windows.
I proposed something like that for spectale some weeks ago. Got refused. https://github.com/eczarny/spectacle/issues/290
I mostly use apps in fullscreen and sometimes need to see 3 /3 apps at the same time, then switch to fullscreen, then back to tiled mode again...
Small aesthetic gaps around windows may not be such a waste of screen estate.