Again, i think that rather than arguing theoreticals, I'll stick by my advice that if you choose to borrow points from Amex, go into it knowing that you'll be on the hook to pay if you don't charge enough to cover your debt within a year.

I'll cede the point that that there are some circumstances where borrowing/buying MR points to transfer over to an airline for an award ticket might be economically feasible compared to buying a ticket.

I also hope that the OP is not using Amex's "Pay with points" feature to get his/her two business class tickets.