No. I wasn't suggesting investing to pay off the mortgage (endowment mortgage), but investing as an alternative use of funds compared to paying off a debt held at low interest rates in a rapidly depreciating currency.
Imagine a more extreme example:
Interest rates 0.1%, Inflation 10%, 30 year term, leverage meaning your 50k becomes say 500k invested.
Now it makes sense to take on as much debt as you can get over say 30 years, and to put off paying it as long as possible, because even after a few years the payments will be quite minor compared to your inflating income, and at the end of the 30 years the debt you have left and the interest payments on it will be trivial compared to your income.
Imagine a more extreme example:
Interest rates 0.1%, Inflation 10%, 30 year term, leverage meaning your 50k becomes say 500k invested.
Now it makes sense to take on as much debt as you can get over say 30 years, and to put off paying it as long as possible, because even after a few years the payments will be quite minor compared to your inflating income, and at the end of the 30 years the debt you have left and the interest payments on it will be trivial compared to your income.