And what does that do exactly? Take a snapshot of the whole screen or just a selected portion? And does it copy to the clipboard or create a file? And where is the file? That shit actually is hard to remember, especially if you don't do it every day. And it is in no sense of the word "intuitive".
I agree that the shortcut is kind of obscure, but the usability seems fine for me.
When you do the key combination your cursor turns into a cross, which by convention is used when cropping images.
Once you crop the portion of the screen it creates the file in the desktop.
I don't think it's that complicated. If you want more control you can always open the screenshot app where you can fiddle with the settings and all.