If you value miles at somewhere between 1 and 2 cents each, then this promotion gives you an extra 1-2% (annualized) return on your $50K (assuming you put in $50K and keep it there 6 months). 1-2% on a money market account is pretty decent these days, so it sounds fine for money market money, but I would not re-orient one's investment strategy just for that 1-2%.

[edited for missing "not"]

[This message has been edited by pynchonesque (edited Feb 24, 2004).]