Thing is, even if it wasn't mandatory, I'd get winter tires either ways, since well, as you can see in my picture, there's a ****load of snow and we're not even in December and that snow lasts up to April. (I ripped my bumper lip at work last year at the end of April on ice/snow.) I do end up travelling in weird time during snowfalls, so it's rather frequent that I am in fresh 2-3 inch of snow. I cannot even imagine the numbers of time I would have got stuck going up hill or anywhere at it even, with all seasons in the conditions we've had in the past weeks.
Now on to add that they have this silly thing here named "White districts", where they just plow the snow without putting any salt/calcium/sand. Pretty slippery. So I just end up using All seasons for summer and Winter for well, winter.