Forgot to answer this question: Because it is so dang hard to actually use those points. Most FTers are really down on Delta because of the lmited redemption opportunities and high redemption costs for the gazillion miles they handed out. There is an interesting thread here entitled something like "Which airline is the stingiest for rewards": Delta is getting the verwhelming majority of the votes in that thread. Take a read at the first few pages, people lay it out pretty clearly there.