The big perk of biking for transportation is that it makes functional commuting more leisurely. Whenever I travel by driving, I feel like I am wasting time just sitting when I could be getting some exercise and fresh air instead if I was cycling.
If you live car-free, leisure-riding is just something you can do when you have the time and the inclination. People used to take leisure drives back when fuel was cheap (some probably still do) and leisure rides on a bike are basically the same except you don't have to buy gas and you're getting some exercise instead of sitting in a motorized cage.