Due to the fees and taxes on DL-issued award tickets, it happens that a DL-issued award ticket means DL collects more cash to get you from A to B and back than another airline's ticket not even using miles. In other words DL gets your miles and even more money than another airline may charge for a ticket (even on the same day) to get you from A to B and back. It's a scheme -- a scheme DL will milk it for all it can and for all its worth while many DL customers are none the wiser until its too late for them.