In my mind, it's a case of po-tA-to/po-tah-to. They're all different names for the same dish. Low-carb and keto-enthusiasts seem to use the term "cauliflower mashed potatoes" more often, though there aren't any potatoes to be found. And restaurant menus seem to err on the side of the fancier-sounding "purée," which is tough to argue with when you're puréeing the cauliflower.