Large open public space to relax. It's easily accessible, with pedestrian access on all sides including a connection to the underground PATH via Sheraton Centre, Toronto Bikeshare station in the Southwest corner (and another to come) and an affordable parking lot (in downtown Toronto relative terms). The TTC also has stops along Bay St (6 bus), Queen St and is a short walk away from the subway.
Many events are held here and fireworks shows are popular on holidays. Many times in the summer, food truck vendors will be lined up around the square. The large fountain doubles as a skating rink in the winter with skate rentals nearby.
No admission. The ambience is less commercial than Yonge-Dundas square and it's definitely more relaxing.
Tip: Go early in the morning to get a picture alone with the sign. Then walk up the street to Bay and Dundas and grab a cheesecake at Uncle Tetsu (opens at 8am) which also has no line in the early morning.