What a lot of people don't know is that you can drag and drop a file/folder icon onto any OS X file open
dialog. The dialog will then browse to that folder or select that file.
And what's more, you can drag the icons from application titlebars and it has the same effect! Try it with icons in file browser trees inside 3rd party OS X apps, AND IT STILL WORKS! Try dropping the icons directly onto textfields that are meant to contain file paths (ones bound to browse buttons) AND IT STILL WORKS!
This is what having a consistently applied collection of user interface controls, and the first party devs dogfooding them, does for an OS.