close all Finder windows on Mac

It looks like Option+Cmd+w is the keyboard shortcut to close all windows of an app. Also, Finder has this method of Option+click on the File menu, which then shows a "Close all" menu item. 

A bit clunky in my opinion. And apparently many people moving from Linux/Windows to Mac have this problem, due to selecting a large number of files and hitting "Get Info..." like I did - MacOS then proceeds to open that many info boxes instead of showing a single window with cumulative info as on Linux/Windows.