Alberta gets too cold for road salt to be used which is why they use gravel. Though, I agree and would like to see gravel used in Ontario as it is much better for the environment. We are seeing a significant rise in the salinity of our rivers and, more concerning, groundwater drinking wells.

In Ontario, sand is typically used outside of cities, at least in Simcoe County. It's remarkably effective at melting ice and snow.

Sand does nothing to melt ice and snow. It's used for traction.

Yes, it's used for traction, but sand will absolutely melt snow and ice. I know from experience. On my low-traffic street, the ploughs only spread sand on intersections and hills (to conserve it, I'm assuming), and when the rest of the street is hard-packed snow and ice, those spots are bare asphalt. It melts it by making it darker, thus absorbing more sunlight. This effect is less pronounced at extremely cold temperatures, and only works during the day.

Grit and salt are two tools used for different temperature.

Salt is better when the weather is close to 0 celcius. Grit is better when it's colder.

I believe salt stops being effective around -12C, so for colder places it's not an option.

In the northeast US I think they typically use a mix of both sand and salt.