>Having both an “Open” command and an “Open, but faster and does less” command
>I personally see this particular feature as redundant (given there is already thumbnailing and a means to open files)
I'm guessing neither of you have actually used QuickLook and/or don't use apps like Photoshop or Illustrator which, even on a fast SSD equipped laptop can take around 30 seconds to open. QuickLook is much more than just a preview.When I'm browsing a folder of my image files and can't remember which of dozens of files is the one I actually want, QuickLook lets me pop open a screen sized modal preview window, which is as good as having that file open in the app. If it's not the file I'm looking for, I hit the up or down arrows and the next or previous file's content is displayed in the already open preview popup. If some of those other image files were created by Illustrator, I've just saved myself an additional ~30 seconds, by not having to open that app too. And, once I find the image I want, I can open it in its associated app directly from a button in the top of the preview pane.
But, even if you're not a graphic designer, QuickLook has its uses for other types of document too. It can preview the content of source code files [with syntax highlighting] preview the rendered output of things like HTML, PDF, Markdown, AsciiDoc etc. You can even scroll through the pages of a multipage document.
This is another timesaver I use all the time. Being able to check the date or bottom line on a received PDF invoice, without opening it... being able to check whether I mentioned something in a letter I sent, without firing up a text editor or word processor... being able to see a rendered representation of what an HTML file contains... etc. etc.