Shoes

So, I went to Macy's on a little fact-finding excursion, searching for what Fall/Winter shoes I'm going to buy when I'm ready (having destroyed last Winter's boots after wearing them everyday for two years). And I saw lots and lots of options, an overwhelming number of options, so I'll have some serious decision-making to do when the time comes. Anyway, can someone please explain the concept of mules or sling-back shoes for Fall/Winter wear? They were all over the place, really cute, fall colors and materials, but backless shoes for a NYC Winter? Are you meant to wear them with stocking/socks or just bare? I don't get it.