I am not surprised at all. WEM is the largest and busiest mall in Canada, and the foot traffic there is constant, consistent and high through the whole year, and it caters to all buyers, from high luxury (see Balenciaga, etc...) to discount retailers.
Southgate is another mall that cracks the top 10 busiest malls in the country and it has a high average ticket per visit. And in a city that has the harsh winters we do, with a relatively high median disposable income, where enclosed malls are still highly successful, makes a lot of sense.