MPI vs paying down principal

[Champ Leong]

I'm being offered the "opportunity" to purchase Mortgage Protection Insurance for $85 per month on a $165,000 loan in the event I go to heaven so I leave a PAID OFF house to my posterity. The insurance payout would decrease each year as the principal decreases. What would be the diff between MPI and simply paying down the principal using the $85 each month I would have used to buy the MPI? TIA!