The problem is people confusing 'snow tyres' with 'winter tyres'. The clue is in the name - they are not snow tyres, they are winter tyres, and are the best tyre for that season.
They work better in the cold, the wet, when it's icy and yes, when it's snowy too. Long term they don't cost any more because you only wear out one set at a time anyway, and now your summer tyres take a break from November to March, they last much longer in terms of months and years.
I bought some in 2010 when the weather was awful, and I was driving a 2-ton, 300bhp RWD Lexus. With winter tyres on (even the cheapo GT Radial ones I bought) the difference in grip was unbelievable. The car went from completely useless to being able to simply drive around, taking care of course, but generally with no more difficulty than in very heavy rain.
Its not just about snow, they work way better on icy, untreated roads and give more grip any time the temperature drops below about 7C. Which is way more often than you think, considering most people drive first thing in the morning (when it's frosty) and again in the evening (dark and much colder than at lunchtime).