The real question is why use Mate.
toolbars/panels, applets (integrated with package manager, i.e. without need to go to site, download, unpack) , a menu usable by mouse (i.e. without touch screen) and screen without areas automatically switching to task manager or what name of it and all of this over stable enough codebase
Who goeth a-borrowing goeth a-sorrowing. -- Thomas Tusser