Maynes discusses the importance of Foley in elevating the overall sound design despite its lower standing in the post sound hierarchy. I couldn't agree more with his perspective, and Douglas Murray has a great point in the comments that Foley adds the "detail and weight that are helpful for believability and to glue the sound effects together."
As an editor, I have spent a lot of my time focusing on Foley. I find it important to communicate with a client the need for Foley and as others have pointed out in the article, Foley can be a great medium for character development and emotional elements.
I had the opportunity as an intern to check out Gary Hecker's work during the post production of The Twilight Saga: Breaking Dawn - Part 2. It was amazing to see how an experienced Foley artist can sync sounds for virtually anything. I could go on and on, but it'd be better to just check him out in action:
I definitely suggest reading the full Designing Sound article and comments section.