The main reason I got the oil pan heater was to prevent common CCV failures that are going to happen at some point, especially if you have short drives in the winter. It basically goos up your CCV system and you either get a vacuum leak, or you suck oil into the engine and you hydrolock it. Google it if you want to scare yourself.
The other benefits of running an oil pan heater is that your oil is nice and warm so less wear on the engine at startup, plus your car warms up quicker so you have heat out of your vents sooner.
The downside is you have to plug it in to work, but I have it on a timer so it only comes on in the morning an hour before I leave for work.