That’s an interesting take on things, and if you can pay off a 30 year mortgage in 5 years, that’s great.

In general, my point about the tax deduction is only one piece. If you look at long term inflation, a 4% interest loan works out to under 1% actual cost, regardless of any tax deduction. Beyond that, if you’re in the process of paying the loan off early and suddenly lose your income and can’t make the next payment, you’re S. O. L. The bank won’t recharacterize your extra payments as your next payment due, and you’ll lose your home.

If you take on paying the loan off in 6 years, that’s a much lower likelihood than if you plan on doing it in 22 years, which is more typically doable.