@Paul Allen
If you were able to invest in a fund that averaged 8% and allowed you to borrow that same amount of money back 5 years later for 4%, all the while still earning 8% in that fund (on the full account value, even including what you borrowed) on average, would you do it?
Would you still do it if you knew that, as time went on, the value in your fund would grow and you could borrow more for 4% and invest in something else that makes 8%---without ever having to explain your reasoning to a loan officer?
How about if the gains in that account value were not taxable? How about if the amount you borrowed--which would eventually be much more than your investment--wasn't taxable?
Would it be a deal breaker if your heirs get an extra million dollars when you die?
Or would you rather just "invest" that money in something called term life insurance where you personally would never see the benefit of and have about a 10% chance your kids might get a million bucks?