Or they could just mean they would pay down the house, which can be a big financial boon, even if not completely paid off. If you are in the US and have a normal 30 year fixed rate mortgage, then paying down 50k means you get to save on the remaining interest due on that 50k - so you don’t just save 50k, but the compounding interest due on that 50k across the remaining liftime of the loan.
Or they could just mean they would pay down the house, which can be a big financial boon, even if not completely paid off. If you are in the US and have a normal 30 year fixed rate mortgage, then paying down 50k means you get to save on the remaining interest due on that 50k - so you don’t just save 50k, but the compounding interest due on that 50k across the remaining liftime of the loan.