Originally Posted by
relangford
This may be a stupid question, but .... Why would the airlines care as long as the miles are being used?
Because they don't particularly want a fungible market in airline miles that makes them closer to currency in terms of liquidity- mileage programs are loyalty programs meant to make you make decisions based on your mileage balance and perks as opposed to costs of the flight, not cashback that you cash out to the highest bidder.
Seriously, don't you think if airlines wanted miles to be easily exchanged for cash at favorable rates... they'd have already done it?