The story behind this accessory is largely one of practicality - as games become increasingly large and complex, the need for increased storage becomes more pressing. With its increased capacity, the Xbox 360 250GB Hard Drive aims to meet this demand.
Gameplay-wise, this device doesn't change how you play your games, but it does make certain tasks easier. When using your Xbox 360 250GB Hard Drive, you can store more game saves and data on one drive, rather than having to switch between multiple drives.