I don't know if this is the right place to comment but I agree with you and noticed a lot of people are equating "survivable" cold/hot with not needing tunnels.

In a city, most people are working in office towers and not outfitting themselves for anything but the most moderate weather, so it's nice to have tunnels that you can comfortably navigate to go to lunch and meetings and whatnot without bundling up. Nobody disagrees it's possible to walk around outside in Toronto winter and it's not that cold, but it's a hell of a lot nicer getting to stay inside when possible.