I'm pretty sure stopping distance and cornering traction are compromised driving a snow tire on dry roads above 50 degrees. I think consciously giving extra room and stopping distance is much easier to manage during that 5% of bad weather driving on an A/T than it is during the 95% of normal driving on a snow tire in warm weather..
I suspect we just all fear the snow and ice risks more than the normal driving conditions. But, it is risky to drive a snow tire on warm dry conditions as well. We just don't acknowledge that risk as much.
There is a reason why 95% of "cars in the ditch" have A/S tires where I live during winter.