Want to start Firefox? type "fir<tab>" in your terminal and hit enter.
Want to see your files? Type "ls" and hit enter. Learn just a tiny bit about pipes, wildcards, and utilities and you can leave those mouse-pushers in the dust.
Or I could use a desktop on expend my limited mental energy on things more relevant to me. It’s far easier for me to remember things in a visual or spatial manner.
But really mac is less about having every square inch of your monitor filled with a dozen different applications sized perfectly to fit the exact information you want on these screens. You can of course do this if you like but thats not really the philosophy.
The philosophy is that this is a real life desktop. Just like papers on your desk. Do you resize papers various ways and print them to maybe 3 inches across and lay them out on your desk such that you can see every paper at once, no space from one page to the next? No. You have piles. You thumb through piles and pull out stuff you need and lay them loosely next to eachother. Nothing is fixed in any constraints. Stuff can overlap or have space in between.
This is exactly how windows management works in macos. It is simply a different philosophy, but it is much closer to how desktop management actually works in real life with a physical desktop and physical papers.