You're missing the bigger point--hopefully this will force GameStop to lower the price of used games.
At risk of stating the obvious
If Gamestop lowers the price of their used games, then the would be lowering their profit margin.
Lowering the profit margin would cause them lower the price at which they buy used games (to increase profit margin)
Lower used game buy prices cause less used games to be sold to Gamestop, which is how GS makes most of their money.
There are also speculation that this may even be a publisher subsidized deal to kill off the majority of used "new" game sales.
That would allow publishers to accurately track the sale of the games and for developers to properly recoup invested cost.
Gamestop could counter, but used games is the bread and butter. All Best Buy has to do is sit back and wait.
Either way its a Win Win situation for us consumers. So let the price/match wars begin.