This sounds like a useful banking product but unfortunately in Canada and the US they mostly try and get us to pay the mortgage quicker and then borrow money ba

This sounds like a useful banking product but unfortunately in Canada and the US they mostly try and get us to pay the mortgage quicker and then borrow money back at a higher rate if we need to. I think this product would lead to people not using other loan products and never overpaying on their mortgage (why would you if you can offset the interest?)