When I want to delete files I can't choose in the context menu between deleting them completely or sending them to trash(!). With the key shorcuts I can delete them completely but I if select a set of files/folders I am asked whether to "delete all" of them or to simply "delete". What is the difference? Whatever I choose it deletes all the selected. So what is the reason for the question if nobody listens. Is it possible to eliminate the useless question?.
When we right click on a folder with no content it only shows delete (cause its one file). But when we right click on a folder with many contents such as folders and documents it will show 'Delete All' to remind you that if you delete the file all the contents inside will be deleted. It makes it obvious that when we select many folders (many is more than one) so it shows 'Delete All'.
But in the end of the day if you press 'Delete All' OR 'Delete' they will end up in the Trash, so no sweat ;)
Hope it helped.