I've just been over in Germany for a few days where although it is not a legal requirement to have winter tyres when it's cold & snowy, but you do however face an on the spot fine if you get stuck & your running summer tyres. I noticed that most cars were running winters, me however opted for a new set of MPSS's which gave me an un riveled advantage when it came to the motorways . But I also found some snow along the way, The MPSS's faired up pretty well until I chickened out & turned round
I hitched a ride with some young ladies one evening & was more than impressed with the traction on a heavily frosted road from the winter tyres fitted to the car. The same road was quite a challenge in the 370 the following morning
So I'd say if your going to drive in the cold weather, winter tyres are definitely a good option.