Presumably it’s just a strong heating element located near where ice is most likely to build up and cause problems, which in normal use would only be active for a few minutes to clear away the ice with minimal disruption to the rest of the freezer. With this it’s been locked on so it quickly heats up the rest of the freezer too. But that’s my guess based on seeing the deicing cycle in a normal consumer fridge, I don’t know how a commercial freezer would actually do this.