Why not? Two words: no alpha. The box pool is the epitome of efficient markets hypothesis--where's the fun in that?
But for those of you who bought a box or two, here's the backtest of the last 44 games. The worst number to hold is a '5'. Any '5-X' or 'X-5' box has a 0.23% chance, so you already need take a $77 haircut on your mark-to-model. There has NEVER EVER been a final or quarter-end score where one team's score ends in '5' and the other team's in 2-8, so if you have one of those, mark it to $0.
The best number to hold is '0', followed by '7', '3', and '4'.
Via my favorite broker.