I think the problem is that you are keyboard-centric and the Finder, since its introduction is mouse-centric. Therefore the assumption is that if you have selected a file, whatever you're going to do to it - 'Open' isn't likely. Afterall, if you were going to open it, you would have double clicked on it, or dragged it on top of an application icon.

You can argue that that's "bad" if you want - and OK. But the daemon will fix if for you.

Similarly, the mechanisms for going up a folder (and there are many) are mouse-centric.