Very much so - WI and other northern states know how to clear their roads. While you will need to slow down a little more while it is snowing it doesn't really matter because someone else will not have winter tires and so force you to slow down to that speed even if you have them. And even if you have them they are better than summer tires, but they are not that much better, you still need to slow down on ice.

Winter tires are very important in places where they get bad weather but don't clear the roads. Those are not generally places people live though.