Unlocks bonus items, extra karts, or premium drivers.
When the eShop eventually sunsets (as seen with the Wii Shop Channel and 3DS eShop), the ability to legally acquire the -UPDATE- files vanishes. While a physical cartridge of BBR exists, it often ships with "Day One" code. If crucial patches (the UPDATE files) were never physically pressed onto later cartridge runs, future archivists would possess an inferior version of the game. Beach Buggy Racing Switch NSP -UPDATE- -eShop-