Though calories burned through exercise aren't usually much to write home about, exercise as a determinant of health is tremendously important.
One of the most challenging things about exercising in this day and age is that we all lead such incredibly hectic lives - that's why I'm such a strong proponent of what I'd call functional exercise whereupon it's exercise that doesn't feel like exercise. Things like gardening, biking to work, family walks etc. all fit into that category and interventions like the one proposed for Montreal can help - a public bike system whereby for a small fee you can simply rent a bike, bike to your destination and then drop the bike off at one of their other locations.
This type of system is hugely popular in Europe including Paris and hopefully will be rolled out (no pun intended) to more Canadian cities.