"Any tire will work adequately well on dry pavement."
I can't agree with that statement. (well maybe adequately but not well)
Winter tires are generally designed to do 3 things
1) better performance on dry roads in cold weather - A good winter tire will stop in 30% less distance than an all season on dry pavement once the temperature drops below about -5C to -10C. And the colder it gets the more the winter tire outperforms. SO if you are in a place like Calgary wher eyou can have no snow for much of the winter but very cold temps - you are still better in a winter tire.
2) better performance on ice - this is the siping on the tire that provide this benefit(or the studs). But of course it is not magic and you still have to allow extra room, lower you speed etc in icey conditions. Some tires actually have walnut(pecan?) shells in them to assist with the ice performance
3) deep snow performance, Depth/type of tread pattern is generally the defining part here. And this generally applies to low speed performance
Like all things where you are trying to do multple things, there are trade offs so you have to find the tire with the best characteristics for the type of driving you do most.
My gut feel and experience has been, if you live in a 4 season climate, you are safer driving with winter tires all year than you are driving with all seasons all year. Of course still better to alternate for the appropriate season.