Someone else pays it off
What a nice idea to think that someone else is paying off your mortgage for you! When you have an investment property, the rental payments you receive may potentially cover the majority of the mortgage repayments (and in some cases, be more than your repayments!), which in turn is paying off your mortgage with little effort.
Future retirement
While retirement might feel like a long way away, it is important to ensure you are looking after your future finances. Investing in property could potentially be useful for your retirement. If you make the right investment you could potentially live off the rental payments (as your loan would be decreasing over time), or you could sell the property at retirement and use the proceeds to maintain your lifestyle.
Understanding the risks: like any investment, there are risks involved. Some of the risks may include (but are not limited to) the income may not meet your expectations, your property value could decline or you may not be able to sell the property when you want. It is important to consider all your options before making a decision.