The 10yr rate of return on the TSX60 is greater than the 10yr Canada bond interest rate - over the long run investing for the future when the investment is returning more than the interest on debt is always the smart move.
Any competent financial advisor will tell you to choose to invest rather than pay off debt if the opportunity to earn more is greater than the cost of maintaining the debt.
My current mortgage term, which expires in 10 days, was a 4yr fixed at 1.74% - I would have been an utter fool to use any extra money to pay down my mortgage quicker over the last 4yrs when I could have taken the quick and idiot proof method and dumped extra money into fixed 1, 2, 3yr GIC’s and earned double that interest at a min. Or, bought a market ETF for the TSX or S&P or NYSE and earned 20+% over a 2, 3 or4yr period.