I was taken aback by the lack of heated seats during my review too. Both reasons mentioned here already - first of all, it just comes across as cheap when you're going to far as to put advanced technology into your car like a touchscreen AND A GAS-HYBRID POWERTRAIN and secondly, the packaging seems strange for the Canadian market. Less equipped cars (that cost $10,000 less) have heated seats as standard equipment. I don't get it either.
As noted, if these things matter, you have to step up to the XLE which isn't crazy expensive, but might be more than some care to spend.