Waterton and Writing on stone are way beyond 200km one way.
Nobody would ever place themselves into Calgary for taking multiple daytrips, especially if they do have a car. These hotspots must make sense for travelers to stay in one place and use as a base, make sense to center oneself, not just "it's reachable if you really want to". By the way if anyone trying to save a buck and no stay in Banff they should stay in Canmore instead, obviously not as nice but def not worth traveling all the way back to Calgary once you get to the Rockies which takes multiple days to see properly.
If we ever split the WHS into multiple sites for reviews then I can try to write about lots of the parks.