The scrambles in Toronto don't prevent pedestrians from crossing the street on a green light; the scrambles are there because there's just so much more pedestrian than car traffic... (I'm thinking Yonge/Dundas here).

Québec City has many as well, but that's because at many intersections, drivers are so aggressive that you don't actually want to cross the street on a green light, lest someone take a turn and run you over, so the scrambles exist for the pedestrians' safety. There, they're actually an abdication to driver-first culture.