Part of this is not energy savings, but food safety - doorless fridges often have some products near the front that aren't kept to the required sub-5C. Meat products often require 0-3C nowadays too, which is an even narrower range and even harder to meet across all products in a doorless fridge.
Lower and more precise temperatures reduces food waste, which indirectly reduces both costs and energy use.
Lower and more precise temperatures reduces food waste, which indirectly reduces both costs and energy use.