He said “returns are far greater”. That’s a pretty definite statement, as opposed to a more accurate “returns could be far greater” 😉
I have BTLs too, 8% sounds about right, but I pay a marginal tax rate of 45% on the income and with the risk of sudden maintenance bills knocking a % or two off that return in any year it’s debatable whether it’s “far” better than the 2.5% mortgage I’m currently paying on my own house. There’s a bit of capital appreciation, sure, but legal fees & capital gains will take a decent chunk of that when you sell. And until you sell it’s just a paper profit anyway. There’s your risk.
Anyway, my point is that unless there’s zero risk then saying you can get much better returns somewhere else is a case of apples and oranges. Why pay off the mortgage ? You can get far better returns by going down the casino and putting it all on red ! :p