The Peace Bridge has become a very important identifier for the city. It's a modern and interesting landmark for a city that (I believe) wants to be modern and interesting as a whole.
It maybe doesn't bring in people specifically to see it necessarily, but it definitely helps create an identity for the city that people are more interested in visiting (or moving to).
Bridge shows up in an amazing amount of tourism and promotion materials. Simple example is the Calgary Red Tag page.
http://www.redtag.ca/Deals/calgary.php