Looks a bit overkill.
I bought a Bern for the winter commute this year and haven't worn it much - though our non-winter this year has contributed to that!
As others said, a good hat or bala under a normal helmet, with a hood (or even a rain cover) on extra cold days will suffice. Some people tape over the vent holes for very cold conditions.
I also find the dial-adjuster in my helmet is great for easily switching from no-hat size to with-hat size.