Well, there's Ontario weather and then there's Toronto weather. :lol:
Toronto tends to get two or three days a year where there is actually a good amount of fresh snow on the roads - usually it's either mostly melted with random icy spots, or "freshly" fallen snow compacted into a slushy, muddy, salty concoction by all the traffic. A/Ts and the old-school knobby snow tires are good for conditions where you can't hope to get the tires to touch asphalt, but with slush and ice, that stuff fills in the small valleys between the stones in the asphalt to create a smooth surface. You need the siping and contact area of a winter tire to be able to grab onto what little rough surface is left. The BGF A/Ts (and likely other severe snow-rated A/Ts) do have the siping, but lack the contact area of a winter tire.