For the simple reason that Canadians want it.
Distant signal came onto the scene, first of all, when you had satellite television. Suddenly you can watch the same program at 6 p.m., 7 p.m., or 8 p.m., etc, by just going to a different region. It's a wonderful convenience for people who are delayed by traffic, by the babysitting, or whatever, to catch the news or their favourite program.