This X 100. The days of banking miles for some unknown future opportunity, whatever the acquisition cost, are over. It is foolish to buy any currency when its value is black-boxed.

In the new dynamic-pricing world, you could spend, say, $1,000 buying miles for future use, then later learn that it takes 2X the purchased miles to get an award ticket you can buy outright for $900. Maybe. Who knows? The only way to win is not to play.